ALK fusions occur in 3-6% of lung cancers and confer sensitivity to ALK-tyrosine kinase inhibitors. However, acquired resistance inevitably develops through multiple mechanisms, limiting the durability of the treatment response. The present report describes the case of a 36-year-old man with ALK-rearranged lung adenocarcinoma treated with the second-generation ALK-tyrosine kinase inhibitor alectinib. At the time of disease progression, molecular analysis revealed the emergence of a KRAS mosaicism. The present report details the molecular evolution of the tumor, from the initial diagnosis to treatment failure. The current report illustrates a compelling mechanism of resistance to ALK inhibition driven by the synchronous emergence of multiple KRAS variants. While previous case reports have documented an isolated KRAS mutation as a potential resistance mechanism to ALK-tyrosine kinase inhibitor therapy, to the best of our knowledge, this is the first report describing such extensive KRAS mosaicism upon failure of alectinib treatment. The present report highlights the importance of reevaluating the molecular profile of the cancer at the time of progression to accurately define the resistance pathway and develop rational therapeutic strategies capable of overcoming this resistance.

Accurate assessment of surgical margins is essential in the treatment of squamous cell carcinoma (SCC) of the upper aerodigestive tract or cutaneous origin, as well as basal cell carcinoma (BCC). Intraoperative frozen-section analysis is the current standard but is time-consuming and requires coordination among surgical and pathology teams. Reflectance confocal microscopy offers rapid, real-time evaluation of surgical margins and may provide diagnostic information comparable to frozen-section analysis, while enabling the development of a reference atlas for tumor visualization. The HISTOBLOC study aims to evaluate the concordance between confocal microscopy and intraoperative frozen-section examination for assessing surgical margins in SCC and BCC. A secondary objective is to compile a confocal imaging reference atlas to document tumor features and support consistent interpretation HISTOBLOC is a prospective, monocentric, randomized pilot study conducted at the Institut de Cancérologie de Lorraine, a nonprofit comprehensive cancer institute. Patients undergoing surgical excision for SCC or BCC have their margins assessed using both confocal microscopy and frozen-section analysis. The study measure concordance between the two methods and the time required for intraoperative margin assessment. Patient recruitment for the study began on July 26, 2023, and was completed in June 4, 2025. All patients were enrolled according to the approved study protocol. Experimental procedures have been conducted in all recruited participants, and data collection has been completed. The results are currently undergoing statistical analysis and interpretation. This protocol describes a study designed to determine whether confocal microscopy can provide rapid, reliable intraoperative margin assessment comparable to frozen-section analysis, and to generate a reference atlas for clinical and research use. ClinicalTrials.gov; NCT05935995; https://clinicaltrials.gov/study/NCT05935995

Objective:To investigate the correlation between positive resection margins and outcomes in patients with pancreatic ductal adenocarcinoma who underwent surgery and adjuvant chemotherapy according to the pivotal trial PRODIGE 24-CCTG PA-6. Background:The primary focus is on elucidating the prognostic significance of specific resection margins, including those associated with the superior-mesenteric vein, medial, and posterior pancreas. Methods:The analysis involved 400 patients across multiple centers in France and Canada. Surgical resection and subsequent adjuvant chemotherapy were core interventions. This study assessed the prognostic impact of resection margins, highlighting the significance of standardized pathology assessments. In addition, the influence of chemotherapy regimen choice, comparing gemcitabine to mFOLFIRINOX, on the implications of positive resection margins was examined. Results:Only 3 margins, superior-mesenteric vein [hazard ratio (HR) = 1.48 (95% CI: 1.11; 1.96); P < 0.001], medial [HR = 1.92 (95% CI: 1.36; 2.73); P < 0.001] and posterior [HR = 1.65 (95% CI: 1.21; 2.24); P = 0.002], had a significant prognostic impact on disease-free survival and were sufficient compared with the 7 recommended margins (Kappa = 0.90; 95% CI: 0.87; 0.94). R1 status was a significant independent prognostic factor for poorer survival in gemcitabine-treated patients [HR = 1.97 (95% CI: 1.23; 3.16); P = 0.005] but lost its significance with mFOLFIRINOX [HR = 1.46 (95% CI: 0.91; 2.35); P = 0.114]. Conclusions:All efforts should be made to evaluate the 3 margins of the highest prognostic value, with the others being secondary. A key finding of this study is the likely effect of mFOLFIRINOX on local invasion in operated patients, which seems to correct the impairment related to margin involvement, probably explaining the improvements in disease-free survival and overall survival.

AIMS:Myxomas are benign soft tissue neoplasms typically driven by activating GNAS mutations. However, a subset lacks this alteration and remains molecularly undefined. Recent reports have implicated MAP3K family gene fusions in rare myxoid neoplasms sharing features with myxoma. METHODS AND RESULTS:In this study, we characterise 39 MAP3K-rearranged myxoid tumours by integrating clinical, histopathological, immunohistochemical and molecular data. The cohort comprised predominantly middle-aged adults, with tumours distributed across a wide anatomic range (limbs, trunk, face), often in superficial locations. Histologically, the tumours were composed of bland spindle or histiocytoid cells embedded in an abundant myxoid stroma with features mimicking cellular myxoma, such as intermediate-to-high cellularity and broad fibrous septa. High-grade pleomorphism and necrosis were consistently absent. Immunohistochemistry revealed frequent CD34 and HMGA2 positivity, a low Ki-67 proliferation index, and preserved PRKAR1A expression. RNA sequencing identified diverse MAP3K gene fusions, most notably MSI2::MAP3K3 and MAP3K8::MAP3K3, alongside several unique fusion partners. Transcriptomic clustering demonstrated a relationship between MAP3K-rearranged tumours, GNAS-mutant myxomas and a proximity with myxofibrosarcomas, while clearly distinguishing them from other myxoid sarcomas. Clinical follow-up indicated an indolent course with no evidence of metastasis and rare local recurrences; notably, one patient with positive surgical margins remained disease-free several years postoperatively. CONCLUSION:MAP3K-rearranged myxoid tumours represent a molecularly distinct subset of benign neoplasms that overlap histologically with cellular myxoma and must be distinguished from low-grade myxofibrosarcoma.

Background:Accurate assessment of surgical margins is essential in the treatment of squamous cell carcinoma (SCC) of the upper aerodigestive tract or of cutaneous origin and of basal cell carcinoma (BCC). Intraoperative frozen section analysis is the current reference standard but is time-consuming and requires coordination between surgical and pathology teams. Ex vivo reflectance confocal microscopy offers rapid, real-time evaluation of surgical margins and may provide diagnostic information comparable to frozen section analysis while enabling the development of a reference atlas for tumor visualization. Objective:The HISTOBLOC study aims to evaluate the concordance between ex vivo confocal microscopy and intraoperative frozen section examination for assessing surgical margins in SCC and BCC. The secondary objectives are to assess diagnostic performance, time savings, clinical outcomes, and the feasibility of remote intraoperative evaluation using confocal microscopy. Methods:HISTOBLOC is a prospective, monocentric, single-arm pilot study conducted at the Institut de Cancérologie de Lorraine, a nonprofit comprehensive cancer center. The protocol plans on conducting a learning phase with 15 patients, followed by 30 consecutive patients, undergoing surgical excision for SCC or BCC (tumor size 1-4 cm), whose margins are assessed with both ex vivo confocal microscopy and frozen section analysis; a minimum of four margin specimens are obtained per surgical procedure. The primary end point is the concordance (sensitivity, specificity, and positive and negative predictive values) between the two methods, with frozen section as the reference standard; the secondary end point is the time required for intraoperative margin assessment. Diagnostic accuracy is analyzed for the learning curve phase, for the post-learning curve phase, and for the overall study population. Results:Recruitment began on July 26, 2023, and ended on June 4, 2025. Statistical analysis and interpretation are ongoing. The final number of participants and of margin specimens included in the analysis, together with the study findings, will be reported in a separate publication. Conclusions:This protocol describes a study designed to determine whether ex vivo confocal microscopy can provide rapid, reliable intraoperative margin assessment comparable to frozen section analysis in head and neck and cutaneous SCC and BCC surgery.

Background: To better understand the importance of New York esophageal squamous cell carcinoma 1 (NY-ESO-1) and human leukocyte antigen (HLA) subtype in treatment decision making, further investigation of their prevalence and prognostic impact among patients with metastatic synovial sarcoma (mSS) is needed. Patients and methods: This was a retrospective clinico-biological cohort study of adults with mSS. Patient data were collected from the French Sarcoma Group NetSARC database and supplemented by electronic medical records. Primary tumor samples were collected and analyzed for NY-ESO-1 expression by immunohistochemistry (IHC) and HLA-A*02 status by RNA sequencing (RNA-seq). The primary cohort included patients with available primary tumor samples; the impact of a larger sample size was explored by including patients who had either a primary or metastatic sample (termed the exploratory cohort). P values are provided for descriptive purposes. Results: In 92 patients with primary tumor samples, similar to 25% (n = 23) were positive for NY-ESO-1 and HLA-A*02 expression (dual positive). Among 106 patients with IHC data, 61% (n = 65) were NY-ESO-1 positive, and among 94 patients with RNA-seq data, 45% (n = 42) were HLA-A*02 positive. The median overall survival (OS) for positive versus negative NY-ESO-1 status was 35.3 and 21.7 months, respectively (unadjusted P = 0.0428). We observed no difference in median OS for HLA-A*02-positive versus -negative and dual-positive patients versus others (both unadjusted P > 0.05). Multivariate analyses of OS showed no prognostic impact for NY-ESO-1 among primary tumor samples and in the exploratory cohort. However, in the latter, we observed an association between NY-ESO-1 expression and OS in the first-line (P = 0.0041) but not in the second-line setting. Conclusions: The primary tumor cohort showed no association between NY-ESO-1 expression and OS (including stratification by HLA-A*02 subtype and treatment line), when adjusting for important prognostic factors, possibly due to small sample sizes.

The landscape of uterine sarcomas is becoming more complex with the description of new entities associated with recurrent driver molecular alterations. Uterine sarcomas, in analogy with soft tissue sarcomas, are distinguished into complex genomic and simple genomic sarcomas. Leiomyosarcomas and undifferentiated uterine sarcomas belong to complex genomic sarcomas group. Low-grade and high-grade endometrial stromal sarcomas, other rare tumors associated with fusion transcripts (such as NTRK, PDGFB, ALK, RET ROS1) and SMARCA4-deficient uterine sarcoma are considered simple genomic sarcomas. The most common uterine sarcoma are first leiomyosarcoma and secondly endometrial stromal sarcomas. Three different histological subtypes of leiomyosarcoma (fusiform, myxoid, epithelioid) are identified, myxoid and epithelioid leiomyosarcoma being more aggressive than fusiform leiomyosarcoma. The distinction between low-grade and high-grade endometrial stromal sarcoma is primarily morphological and immunohistochemical and the detection of fusion transcripts can help the diagnosis. Uterine PEComa is a rare tumor, which is distinguished into borderline and malignant, according to a risk assessment algorithm. Embryonal rhabdomyosarcoma of the uterine cervix is more common in children but can also occur in adult women. Embryonal rhabdomyosarcoma of the uterine cervix is almost always DICER1 mutated, unlike that of the vagina which is wild-type DICER1, and adenosarcoma which can be DICER1 mutated but with less frequency. Among the emerging entities, sarcomas associated with fusion transcripts involving the NTRK, ALK, PDGFB genes benefit from targeted therapy. The integration of molecular data with histology and clinical data allows better identification of uterine sarcomas in order to better treat them.

Detailed charecteristics and insertions for all cases

Purpose:To retrospectively identify clinical, pathologic, or imaging factors predictive of local relapse (LR) after preoperative radiotherapy (RT) for soft tissue sarcomas (STS). Methods and Materials:This is a retrospective multicenter study of patients who underwent preoperative RT and surgery for limb or trunk wall STS between 2007 and 2018 in French Sarcoma Group centers and were enrolled in the "Conticabase". Patterns of LR were investigated taking into account the multimodal response after preoperative RT. Diagnostic and surgical samples were compared after systematic review by expert pathologists and patients were stratified by tumor grade. Log-rank tests and Cox models were used to identify prognostic factors for radiation response and LR. Results:257 patients were included; 17 % had low-grade (LG), 72.5 % had high-grade (HG) sarcomas. In HG group, tumors were larger, mostly undifferentiated, and displayed more necrosis and perilesional edema after RT. Median follow-up was 32 months. Five-year cumulative incidence of LR was 20.3 % in the HG group versus 9.7 % in the LG group (p = 0.026). In multivariate analysis, trunk wall location (HR 6.79, p = 0.012) and proportion of viable tumor cellularity ≥ 20 % (HR 3.15, p = 0.018) were associated with LR. After adjusting for tumor location, combination of histotype and cellularity rate significantly correlated with LR. We described three prognostic subgroups for HG sarcomas, listed from the highest to lowest risk: undifferentiated sarcoma (US) with cellularity rates ≥ 20 %; non-US (NUS) with cellularity rates ≥ 20 % or US with cellularity rates < 20 %; and NUS with cellularity rates < 20 %, which shared similar prognostic risks with LG sarcomas. Conclusions:HG and LG tumors have different morphological and biological behaviors in response to RT. Combination of cellularity rate with histotype could be a major prognostic for LR. Patients with undifferentiated HG sarcomas with cellularity rates ≥ 20 % after preoperative RT had the highest risk of LR and disease-specific death.

BACKGROUND:We investigated the impact of the implementation of a network of reference centers for sarcomas (NETSARC) on the care and survival of sarcoma patients in France since 2010. PATIENTS AND METHODS:NETSARC (netsarc.org) is a network of 26 reference sarcoma centers with specialized multidisciplinary tumor boards (MDTBs), funded by the French National Cancer Institute (INCa) since 2010. Its aims are to improve the quality of diagnosis and care of sarcoma patients. Patients' characteristics, treatments, and outcomes are collected in a nationwide database. The objective of this analysis was to compare the survival of patients in three periods: 2010-2012 (non-exhaustive), 2013-2015, and 2016-2020. RESULTS:A total of 43 975 patients with sarcomas, gastrointestinal stromal tumors (GISTs), or connective tissue tumors of intermediate malignancy were included in the NETSARC+ database since 2010 (n = 9266 before 2013, n = 12 274 between 2013 and 2015, n = 22 435 in 2016-2020). Median age was 56 years, 50.5% were women, and 13.2% had metastasis at diagnosis. Overall survival was significantly superior in the period 2016-2020 versus 2013-2015 versus 2010-2012 for the entire population, for patients >18 years of age, and for both metastatic and non-metastatic patients in univariate and multivariate analyses (P < 0.0001). Over the three periods, we observed a significantly improved compliance to clinical practice guidelines (CPGs) nationwide: the proportion of patients biopsied before surgery increased from 62.9% to 72.6%; the percentage of patients presented to NETSARC MDTBs before first surgery increased from 31.7% to 44.4% (P < 0.0001). The proportion of patients with R0 resection on first surgery increased (from 36.1% to 46.6%), while R2 resection rate decreased (from 10.9% to 7.9%), with a better compliance and improvement in NETSARC centers. CONCLUSIONS:The implementation of the national reference network for sarcoma was associated with an improvement of overall survival and compliance to guidelines nationwide in sarcoma patients. Referral to expert networks for sarcoma patients should be encouraged, though a better compliance to CPGs can still be achieved.

Le panorama des sarcomes utérins se complexifie de plus en plus avec la description de nouvelles entités associées à des altérations moléculaires récurrentes. Les léiomyosarcomes et les sarcomes utérins indifférenciés sont des sarcomes à génomique complexe. Les sarcomes du stroma endométrial de bas grade et de haut grade, d’autres sarcomes associés aux transcrits de fusion (tels que NTRK, PDGFB, ALK, RET ROS1) et le sarcome utérin déficient en SMARCA4 sont des sarcomes à génomique simple. Le léiomyosarcome est le sarcome utérin le plus fréquent suivi par les sarcomes du stroma endométrial. Il existe trois différents sous-types histologiques de léiomyosarcome (fusiforme, myxoïde, épithélioïde), les léiomyosarcomes myxoïde et épithélioïde étant plus agressifs que le léiomyosarcome fusiforme. La distinction entre un sarcome du stroma endométrial de bas grade et de haut grade est tout d’abord morphologique et immunohistochimique. La mise en évidence des transcrits de fusions aide au diagnostic. Définitivement reconnu comme entité distincte parmi les tumeurs mésenchymateuses gynécologiques, le PECome utérin fait partie des tumeurs rares. Grâce à des algorithmes d’évaluation du risque, les PEComes utérins sont différentiés en borderline et en malins. Le rhabdomyosarcome embryonnaire du col utérin survient typiquement chez l’enfant, mais peut s’observer également chez la femme adulte. Le rhabdomyosarcome embryonnaire du col utérin est presque toujours DICER1 muté, à la différence de celui du vagin qui est DICER1 sauvage, et de l’adénosarcome qui peut être DICER1 muté mais en moindre fréquence. Parmi les entités émergentes, les sarcomes associés aux transcrits de fusion impliquant les gènes NTRK, ALK, PDGFB bénéficient d’une thérapeutique ciblée. L’intégration des données moléculaires avec l’histologie et la clinique permet de mieux identifier les sarcomes utérins afin de mieux les traiter.

Background Ovarian pseudomyxoma peritonei (OPMP) are rare, without well-defined therapeutic guidelines. We aimed to evaluate cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) to treat OPMP. Methods Patients from the French National Network for Rare Peritoneal Tumors (RENAPE) database with proven OPMP treated by CRS/HIPEC and with histologically normal appendix and digestive endoscopy were retrospectively included. Clinical and follow-up data were collected. Histopathological and immunohistochemical features were reviewed. Results Fifteen patients with a median age of 56 years were included. The median Peritoneal Cancer Index was 16. Following CRS, the completeness of cytoreduction (CC) score was CC-0 for 9/15 (60%) patients, CC-1 for 5/15 (33.3%) patients, and CC-2 for 1/15 (6.7%) patients. The median tumor size was 22.5 cm. After pathological review and immunohistochemical studies, tumors were classified as Group 1 (mucinous ovarian epithelial neoplasms) in 3/15 (20%) patients; Group 2 (mucinous neoplasm in ovarian teratoma) in 4/15 (26.7%) patients; Group 3 (mucinous neoplasm probably arising in ovarian teratoma) in 5/15 (33.3%) patients; and Group 4 (non-specific group) in 3/15 (20%) patients. Peritoneal lesions were OPMP pM1a/acellular, pM1b/grade 1 (hypocellular) and pM1b/grade 3 (signet-ring cells) in 13/15 (86.7%), 1/15 (6.7%) and 1/15 (6.7%) patients, respectively. Disease-free survival analysis showed a difference ( p = 0.0463) between OPMP with teratoma/likely-teratoma origin (groups 2 and 3; 100% at 1, 5, and 10 years), and other groups (groups 1 and 4; 100%, 66.6%, and 50% at 1, 5, and 10 years, respectively). Conclusion These results suggested that a primary therapeutic strategy using complete CRS/HIPEC for patients with OPMP led to favorable long-term outcomes.

4160 Background: Pancreatic adenocarcinoma (PDAC) has a poor prognosis. Only 10-15% of patients present with resectable tumors upfront, and most patients develop recurrence and die prematurely. The data are incongruous when considering R1 status, direct invasion is not consistently a significant prognostic factor. It is recommended that 7 margins be identified for surgery: the bile duct, pancreatic neck, proximal and distal duodenum, superior mesenteric vein (SMV), superior mesenteric artery (SMA), and posterior pancreas. By analyzing data from the PRODIGE 24-CCTG PA-6 trial that validated the mFOLFIRINOX regimen in adjuvant setting, our main objective was to analyze the prognostic value of margin involvement on disease-free survival (DFS). Methods: The protocol recommended that the surgeon inked the resection margins. R1 was defined as direct tumor margin infiltration within 1 mm of one or more resection margins. All patient data were re-evaluated centrally by an external review committee including pathologists, surgeons, and medical oncologists to verify key prognostic factors, including inking and filling of resection margins. Results: Among the 400 patients included in the study, the median number of documented margins was 6, IQR (5-7). In 214 patients (53.5%), fewer than 7 margins were reported. The most common margin involvement was on the SMV groove (28.3%), posterior margin (21%), SMA (14.5%), and pancreatic neck transection (5.3%). Margin inking was performed in 64.9% of cases. Misclassification of the R1 status concerned 24.1% of the files after centralized review. When positive, only 3 margins (SMV groove, median and posterior) were significant prognostic factors in unifactorial analysis (all p < 0.01). When combined, one R1 margin among these three had independent prognostic value in multivariable analysis. In multivariate analysis, DFS was significantly different by quality of resection margins in the gemcitabine arm (HR 95% CI 1.97 [1.23;3.16]; p = .005) but not in the mFOLFIRINOX arm (HR 95% CI 1.46 [0.91;2.35]; p = .114). Conclusions: Few studies have examined the prognostic implications of each margin. We consider that every effort should be made to evaluate the 3 best prognostic margins. One finding of this work is the likely effect of mFOLFIRINOX on local invasion in operated patients. It seems that this chemotherapy regimen (unlike gemcitabine) corrects the alteration related to margin involvement, probably explaining all or part of the improved survival. Therefore, the value of additional therapies, such as cloture radiotherapy, should be evaluated in patients with unknown marginal status or in those who did not benefit from mFOLFIRINOX chemotherapy. A patient who received mFOLFIRINOX as adjuvant therapy is more likely to recur with distant metastasis (80%) and with a better survival of 28 months. Clinical trial information: NCT01526135 .

Based on HER2 expression using immunohistochemistry (IHC) and HER2 gene amplification using in situ hybridization (ISH), breast cancers (BC) are usually classified, into HER2 positive (IHC 3+ or IHC 2+/ISH+) and HER2 negative (IHC 0, IHC 1+ or IHC 2+/ISH-). Recently, HER2-low breast cancers (HER2-low BC) emerged as a new subtype defined as IHC1+ or IHC2+/ISH- tumors. HER2-low BC represent more than half of all BC. Consistently with the clinical activity of HER2 antibody-directed chemotherapy (ADC) in HER2-low BC, this subtype should be identified to enable early set-up of therapy. Since HER2-low BC identification could be equivocal using conventional IHC and ISH, we evaluated the performance of NGS for integrated diagnostic including HER2 copy number analysis. BC tumor specimens were analyzed using IHC and ISH as performed routinely. NGS was performed using a custom capture based 51-gene panel, including BC molecular target genes such as ESR1, PIK3CA, AKT1, ERBB2, TP53, BRCA1 and BRCA2. Gene mutations as well as copy number variation (CNV) and Microsatellite Instability (MSI) were determined. Thirty-one FFPE BC tumor specimens were classified using IHC and ISH into 11 HER2-positive (IHC2+ ISH+ and IHC3+), 10 HER2-negative (IHC 0) and 10 HER2-low cancers (IHC1+ and IHC2+ ISH-). Using NGS, CNV values for ERBB2 gene were significantly (p<0.001) different between HER2 negative, HER2low and HER2- positive tumors with mean CNV values of 2.0 (SD=0.3), 1.9 (SD=0.3) and 7.8 (SD=6.8), respectively. Using 3.25 as cutoff value for CNV, 90% concordance of HER2 amplification status was achieved between ISH and NGS. Using NGS, additional drug-targetable gene mutations as well as amplifications were detected in 68% (21/31) and 19% (6/31) of the cases, respectively. One case of MSI was detected in a HER2-negative and ISH unamplified case. These results show that in HER2 IHC positive (scores 1+ to 3+) BC, CNV determination using NGS allows the identification of HER2-low status simultaneously with the detection of multiple molecular target genes while sparing tissue samples. This workflow could support molecular board decision between HER2-ADC or other targeted therapies.

Based on immunohistochemistry (IHC) and in situ hybridization (ISH), HER2-low breast cancers (BC) subtype-defined as IHC1+ or IHC2+/ISH- tumors-emerged and represent more than half of all BC. We evaluated the performance of NGS for integrated molecular characterization of HER2-low BC, including identification of actionable molecular targets, copy number variation (CNV), and microsatellite instability (MSI) analysis. Thirty-one BC specimens (11 HER2+, 10 HER2-, and 10 HER2-low) were routinely analyzed using IHC and ISH, and were selected and analyzed using NGS for gene mutations including ESR1, PIK3CA, AKT1, ERBB2, TP53, BRCA1, and BRCA2, CNV, and MSI. CNV values for the ERBB2 gene were significantly (p < 0.001) different between HER2+, and either HER2-low or HER2- tumors with mean values of 7.8 (SD = 6.8), 1.9 (SD = 0.3), and 2.0 (SD = 0.3), respectively. Using 3.25 as the cutoff value, 96.8% overall concordance of HER2 status was achieved between IHC and NGS compared to IHC and ISH. Using NGS, gene mutations and amplifications were detected in 68% (21/31) and 19% (6/31) of the cases, respectively. One case of MSI was detected in a HER2-negative and ISH unamplified case. Beside IHC, NGS allows the identification of HER2-low subtype simultaneously, with the detection of multiple actionable gene mutations being helpful for molecular board treatment selection.

One-step nucleic acid amplification (OSNA) is a molecular procedure used intraoperatively for the detection of sentinel lymph node (SLN) metastases. The aim of the present study was to define a cut-off of cytokeratin (CK)19 mRNA copy number predictive of positive completion axillary lymph node dissection (ALND). The OSNA procedure was employed for SLN analysis in 812 patients with T1-T2 N0 breast cancer. A total of 197 patients with SLN metastases were retrospectively analyzed. A total of 40 patients (20%) had non-SLN metastases. Receiver operating characteristics curve analysis established a cut-off of 5,000 CK19 mRNA copy number with 75% sensitivity and 72% specificity. The positive and negative predictive values were 40.5 and 92%, respectively. Multivariate analysis showed that this cut-off and tumor localization in the outer or lower-outer quadrant of the breast were significantly associated with non-SNL involvement (P<0.001 and P=0.025, respectively). The findings of the present study support the conventional cut-off of 5,000 copies for intraoperative decision to perform ALND, whereas ALND can safely be avoided in patients with tumor located outside the outer or lower-outer quadrant of the breast if the CK19 mRNA copy number is <5,000.

The landscape of uterine sarcomas is becoming increasingly complex with the description of new entities associated with recurrent molecular alterations. Uterine sarcomas, as well as soft tissue sarcomas, can be distinguished into complex genomic sarcomas and simple genomic sarcomas. Leiomyosarcoma and pleomorphic type undifferentiated uterine sarcoma belong to the first group. Low-grade and high-grade endometrial stromal sarcomas, NTRK, COL1A1::PDGFB, ALK, RET, ROS1 associated sarcomas, and SMARCA4 deficient uterine sarcoma belong to the second group. Leiomyosarcoma is the most common uterine sarcoma followed by endometrial stromal sarcomas. Three different histologic subtypes of leiomyosarcomas are recognized with distinct diagnostic criteria and different clinical outcomes, the myxoid and epithelioid leiomyosarcomas being even more aggressive than the fusiform type. The distinction between low-grade and high-grade endometrial stromal sarcoma is based first on morphology and immunohistochemistry. The detection of fusion transcripts helps in the diagnosis. Definitely recognized as a separate entity, uterine PEComa is a rare tumor whose diagnostic criteria are being recently defined. Uterine PEComa has a specific algorithm stratifying the tumors into uncertain malignant potential and malignant tumors. Embryonal rhabdomyosarcomas of the uterine cervix are not restricted to children but can also be observed in adult women and are almost always DICER1 mutated, unlike embryonal rhabdomyosarcoma of the vagina which are DICER1wild-type, and adenosarcoma which can be DICER1 mutated but with less frequency. As sarcomas associated with fusion transcripts involving the NTRK, ALK, COL1A1::PDGFB genes can benefit from targeted therapy, systematic detection are now relevant especially for patients with high risk of relapse or in recurrent setting. The integration of molecular data with dedicated expert pathology review for histology and clinical data allows better identification of uterine sarcomas in order to better treat them.

Introduction. Since 2010, the network of rare malignant tumors of the ovary (TMRG) was developed to optimize the management of patients, also allowing a histological second opinion of rare ovarian tumors. The aim of this work was to study the contribution of second opinion to improve histological diagnostic accuracy on ovarian rare malignant tumors included in the TMRG database. Material and methods. Histological data of patients diagnosed with a rare ovarian tumor included in TMRG network over a one-year period (2018) were collected. Initial diagnoses were compared with second opinion from national gynecological pathologist experts. The modalities of histological second opinion requests were studied, as well as the histological characteristics of the tumors. The discordances were classified as minor (if the modification of histological diagnosis did not change patient management) and major (if the patient management can be modified). Results. Of 1185 included patients, 937 matched the inclusion criteria. Full concordance between primary diagnosis and expert second opinion was reached in 611 cases (65,3%), minor discordance was seen in 114 (12,2%) and major discordance in 209 (22.3%) of cases. In systematic review requested by the network. 26% (n = 137) of cases were reported with a change in histological diagnosis, while the change concerned 44% (n = 186) of cases for a second opinion spontaneously requested by the initial pathologist The discrepancies concerned all categories of ovarian tumors, with a majority of mucinous tumors (43% of major discordances), followed by stromal and sex-cord tumors (13.8% of major discordances) and clear cell tumors (12,4% of major discordances). Conclusion. This analysis confirms the diagnostic difficulty of ovarian tumors, due to their rarity and morphological heterogeneity. French pathologists are aware of these difficulties and spontaneously refer ovarian tumors with unusual histology for a second opinion and collaborate with rare tumor networks for systematic review. (C) 2022 Elsevier Inc. All rights reserved.

Previous studies have found that use of hexaminolevulinate (HAL) and blue light cystoscopy (BLC) during treatment of bladder cancer had a positive impact on overall survival after later cystectomy, indicating a potential treatment effect beyond improved diagnostic accuracy. The aim of our study was to determine whether HAL and BL mimicking clinically relevant doses in an orthotopic rat model could have therapeutic effect by inducing modulation of a tumor-specific immune response. We also assessed whether administration with a checkpoint inhibitor could potentiate any effects observed. Rats were subjected to HAL BL alone and in combination with anti-PD-L1 and assessed for anti-tumor effects and effects on immune markers. Positive anti-tumor effect was observed in 63% and 31% of rats after, respectively, 12 and 30 days after the procedure, together with a localization effect of CD3+ and CD8+ cells after 30 days. Anti-tumor effect at 30 days increases from 31% up to 38% when combined with intravesical anti-PD-L1. In conclusion, our study demonstrated treatment effects with indications of systemic immune activation at diagnostic doses of HAL and blue light. The observed treatment effect seemed to be enhanced when used in combination with intravesically administrated immune checkpoint inhibitor.