The expression of members of the GATA family of proteins and their prognostic value has been previously investigated in different tissues; however, there is limited data on the role of GATA6 and GATA3 in esophageal squamous cell carcinoma (SCC) and adenocarcinoma (ADC). We aimed to assess the distinct expression and prognostic roles of GATA6 and GATA3 in 52 cases of esophageal carcinoma and to correlate these findings with clinicopathologic parameters and patient outcomes. GATA6 was expressed in 55% of ADC cases, 12.5% of SCC cases, and 15% of Barrett esophagus (BE) cases ( P =0.000). GATA6 was significantly associated with high tumor grade and stage ( P =0.015 and 0.011, respectively), perineural invasion ( P =0.004), tumor size ( P =0.004), and lymph node status ( P =0.037). GATA3 was expressed in 21.9% of SCC, while no expression was detected in ADC and BE ( P =0.027). GATA3 was significantly associated with low tumor grade and stage ( P =0.031 and 0.007, respectively). GATA6 was associated with poor overall survival (OS) ( P =0.000) and poor disease-free survival (DFS) ( P =0.000). No association was found between GATA3 expression and OS ( P =0.477) and DFS ( P =0.096). In conclusion, esophageal ADC was positive only for GATA6, whereas SCC was positive for both markers, with higher GATA3 expression. GATA6 may be a poor prognostic indicator for esophageal carcinoma.
Cancer is one of the leading causes of morbidity and mortality worldwide, with lung cancer ranked among the most lethal malignancies. A key hallmark of cancer progression is neovascularization, primarily mediated by vascular endothelial growth factor (VEGF), which stimulates vasculogenesis and angiogenesis. In parallel, the transcription factor nuclear factor of kappa B (NFκB) plays a critical role in inflammation, immune regulation, and tumor development by modifying numerous signaling pathways. In this study, we aimed to compare the expression levels of VEGF and NFκB in mouse embryonic stem cells (mESCs), fibroblasts, and lung cancer cells (LCCs) to probe cell-type-specific regulatory profiles. Protein levels were evaluated using immunofluorescence staining and quantified by corrected total cell fluorescence (CTCF), while mRNA expression was analyzed to relate protein-level findings. Our results showed no significant difference in NFκB protein expression among the 3-cell types. In contrast, VEGF protein expression was significantly higher in fibroblasts and lung cancer cells compared with embryonic stem cells. These findings propose that while NFκB may play a stable regulatory role across cell types, VEGF exhibits a dynamic expression pattern linked with angiogenic potential and cellular differentiation status.
The Hippo pathway has been implicated in the tumorigenesis of hepatocellular carcinoma (HCC). We aimed to determine the expression of Hippo pathway-related proteins in HCC using immunohistochemical staining and compare the data among patients with different underlying clinical background diseases. We collected 40 resected HCC formalin-fixed paraffin-embedded samples and categorized them into 4 groups according to pre-existing conditions [17 samples of alcohol consumption (HCC-A) and 6, 8, and 9 samples with hepatitis B virus infection (HCC-B), hepatitis C virus infection (HCC-C), and metabolic diseases (HCC-M), respectively]. Using immunohistochemistry, we investigated the Hippo pathway-related proteins YAP1, CADM1, and SOX9. Hypertension was the most common disease (72.5%) among patients with HCC, followed by diabetes mellitus (47.5%). Regarding the background liver disease, significant findings of steatohepatitis (SH) were observed in the HCC-A (35.3%) and HCC-M (88.9%) groups compared with those in the HCC-B (16.7%) and HCC-C (0%) groups. A significant finding of metabolic dysfunction-associated SH (MASH) was also observed in the HCC-M group (88.9%), and liver cirrhosis was predominantly observed in the HCC-C group (100%). Twenty-seven patients had Hippo-inactive status, and 13 patients had active status. SH was more predominant in the HCC-M group with Hippo inactivity (100%) than in the HCC-A group (50.0%). The average tumor size was significantly larger in the Hippo-inactive group than in the Hippo-active group. Hippo pathway-associated proteins could serve as potential therapeutic targets for MASH and MASH-related HCC if the Hippo pathway is inactivated.
The use of ready-to-use (RTU) antibodies in pathology laboratories has increased due to regulatory changes and the need for standardized, efficient diagnostic workflows. This study compares the performance of RTU antibodies from 2 major suppliers, Agilent (Dako Omnis platform) and Roche (BenchMark Ultra Plus system) in a Norwegian hospital setting. A total of 125 RTU antibodies were evaluated using vendor-recommended protocol settings (VRPS) and scored according to NordiQC standards. Results showed that 58 out of 62 antibodies on the Dako Omnis platform were rated as "optimal" or "good," compared with 37 out of 63 on the BenchMark Ultra Plus. Notably, 26 (41.3%) of Roche antibodies were rated "borderline" or "poor." Our study shows that several RTU antibodies perform suboptimally with VRPS. This highlights the importance of thorough validation and verification of RTU antibodies before diagnostic use. The findings underscore the need for reliable protocols from manufacturers and encourage interlaboratory collaboration to improve diagnostic consistency and quality assurance.
Programmed death-ligand 1 (PD-L1) is a predictive biomarker in various cancers. In colorectal cancer, PD-L1 expression evaluation is not part of the routine examination and standardized evaluation methods are lacking. This study aimed to examine inter-rater agreement in PD-L1 expression evaluation in patients with colon cancer (CC) using different manual scoring methods, and to compare the manual methods to a digital evaluation. Two pathologists evaluated 188 PD-L1-stained slides from patients with CC. The tumor proportion score (TPS) and immune cell score (ICS) were categorized as <1%, 1-9%, and ≥10% positivity and the combined positive score (CPS) as <1, 1-9, and ≥10 positivity. Inter-rater agreement was assessed using different cutoffs and consensus scores were compared with an in-house-developed digital algorithm quantifying PD-L1. Percentage agreement was 98.9% for TPS, 85.6% for ICS, and 88.8% for CPS. When dichotomized using 1% or 10% for ICS and 1 or 10 for CPS as cutoffs, the percentage agreement increased. Only 2 cases presented with a consensus TPS ≥1%, while 96.8% had a consensus ICS of <10%, and 98.4% a consensus CPS of <10. When the digital PD-L1 score was categorized into low and high, the highest agreement with the manual evaluations was reached using the third quartile as a cutoff. Conclusively, high inter-rater percentage agreements were obtained for all scoring methods, although kappa values varied. Results comparable to the manual evaluation were reached with a digital algorithm. A digital approach can potentially eliminate inter-rater variability. Clinically relevant cutoff values remain to be determined.
BACKGROUND:Breast cancer is the most common form of cancer diagnosed in women. Breast cancer cells gain the expression of mesenchymal-specific genes in a process known as epithelial-mesenchymal transition (EMT). RhoJ, a small Rho GTPase, is a key regulator that promotes resistance to a wide range of chemotherapeutic agents in epithelial-mesenchymal transition tumor cells. METHODS:Sixty-three cases of invasive breast carcinoma and 10 cases of normal breast tissue were collected to examine the protein's expression of RhoJ in epithelial and stromal cells. Two pathologists performed the H-Score in a blinded fashion. RESULTS:Normal ductal cells expressed RhoJ moderately to sometimes intensely. Normal breast stroma showed low to moderate expression in 95% of cases. All malignant ductal cells, except for 2 cases of metaplastic carcinoma, showed diffuse and intense expression. Stromal cells in invasive areas showed low to moderate expression. We found no statistically significant difference in RhoJ expression between carcinoma and normal breast tissue or between carcinoma subtypes (no special type vs. lobular; triple negative vs. luminal). Interestingly, we found a lower expression of RhoJ in metaplastic carcinomas (2 cases of spindle cell variants). CONCLUSIONS:High levels of RhoJ expression in most breast carcinomas suggest it could be a valuable therapeutic target. However, further studies involving a larger patient cohort are necessary to validate these findings.
Ductal carcinoma in situ (DCIS) is a noninvasive form of breast cancer that accounts for 15% to 25% of all new breast cancer diagnoses. Clinical management approaches for DCIS include surgical excision, radiotherapy, and endocrine therapy (for patients with estrogen receptor (ER)-positive disease). Active surveillance is also being investigated for patients with low-risk disease. Pathologist assessment of nuclear grade as well as ER expression by immunohistochemistry is currently used to inform clinical decision-making. Exploratory protein biomarkers in DCIS include HER2, p16, p53, and Ki-67. Our study evaluated pathologist interreader agreement for the following immunohistochemical stains applied across 40 cases of DCIS: ER, PR, HER2, p16, Ki-67, and p53. We found that pathologist agreement was good to excellent for assessment of ER and PR (progesterone receptor), both with regard to the percent of cells staining as well as staining intensity (ICC/kappa: 0.76-0.96 for ER, 0.69-0.98 for PR). Interreader agreement was also good to excellent for HER2 interpretation (ICC/kappa: 0.78-0.97). For additional exploratory biomarkers, including p16, p53, and Ki-67, interreader agreement ranged from fair to good, likely reflecting a lack of pathologist training and less familiarity with these biomarkers in the context of DCIS. Our findings suggest that investigators should take potential interreader variability into consideration when designing clinical trials and exploratory biomarker studies.
Patient-derived organoids (PDOs) offer a powerful in vitro platform to model cancer biology, investigate therapeutic responses, and personalize treatment strategies. Here, we describe a comprehensive and reproducible protocol for establishing 3-dimensional (3D) organoid cultures from surgically resected triple-negative breast cancer (TNBC) samples. Fresh TNBC surgical tissues were processed using a standardized enzymatic and mechanical dissociation protocol followed by 3D culture in Matrigel. Organoids were expanded, cryopreserved, and characterized through histology, immunohistochemistry (IHC), and whole-exome sequencing (WES). Immunophenotypic and genomic concordance was assessed between PDOs and their paired tumors. Organoids were successfully established from resected TNBC tissues, displaying histologic, immunohistochemical, and genomic fidelity supporting high-throughput and personalized research applications.
Gastrointestinal stromal tumors (GISTs) with PDGFRA mutations represent a distinct subset with characteristic clinicopathological features and important therapeutic implications. The diagnostic performance of PDGFRA immunohistochemistry (IHC) as a phenotypic correlate of PDGFRA mutation status requires further evaluation. This study aimed to assess the diagnostic performance and reproducibility of PDGFRA IHC against PDGFRA mutation status as the reference standard. A total of 117 tumors were analyzed (19 PDGFRA -mutant, 40 non- PDGFRA , 49 GISTs of undetermined genotype, 9 non-GIST mimics). IHC for KIT, DOG1, CD34, and PDGFRA was performed on full sections and tissue microarrays, and 3 pathologists independently scored intensity, extent, and Golgi-pattern accentuation. PDGFRA -mutant GISTs were predominantly gastric with epithelioid or mixed morphology. Sixteen carried D842V, whereas 3 had exon 18 deletion or exon 12 mutations. KIT expression was reduced (47.4%) compared with non- PDGFRA -mutant GISTs (85%), while DOG1 remained consistently positive. Overall, PDGFRA expression was observed in 94.7% of PDGFRA -mutants compared with 32.5% of non- PDGFRA -mutants ( P< 0.001), and Golgi-pattern accentuation was present in 89.5% (17/19) of PDGFRA -mutants versus 7.5% (3/40) of molecularly confirmed non- PDGFRA -mutants ( P <0.001). Among non-GIST mimics, only a monophasic synovial sarcoma showed diffuse PDGFRA positivity. Interobserver agreement for PDGFRA was substantial (κ=0.691). PDGFRA IHC showed 95% sensitivity and 78% specificity but did not distinguish D842V from non-D842V variants. PDGFRA IHC correlates with PDGFRA -mutant genotype when diffuse Golgi-type staining is observed in a gastric epithelioid or mixed tumor showing reduced KIT expression. However, therapeutic selection-particularly for avapritinib-requires precise detection of D842V variants, which mandates molecular sequencing.
Leucine-rich repeat-containing 15 (LRRC15) is a membrane protein whose overexpression has been linked to poorer survival outcomes in various malignant neoplasms. However, its role in distal extrahepatic bile duct carcinoma (DBDC) remains unclear. LRRC15 protein expression in tumor cells and stroma was evaluated with 196 surgically resected DBDCs, and compared with clinicopathological variables, including patients' overall survival (OS) and recurrence-free survival (RFS). LRRC15 protein expression was identified in stroma of 21 DBDCs (11%) and tumor cells in 67 cases (34%). On the basis of the combined expression patterns of LRRC15, DBDCs were classified into 4 groups: LRRC15 cancer+/stroma- (25%), cancer-/stroma+ (2%), cancer+/stroma+ (9%), and cancer-/stroma- (64%). The stromal LRRC15+ group exhibited more frequent pancreatic invasion compared with the stromal LRRC15- group ( P =0.004*). The LRRC15 cancer+/stroma+ group showed the most frequent pancreas invasion ( P =0.016*). The patients with stromal LRRC15+ group had significantly worse OS (5-year survival rate, 15.4% vs. 31.6%; P =0.013*) and RFS (19.1% vs. 38.9%; P =0.005*) compared with those in the stromal LRRC15- DBDCs. Stromal LRRC15 expression was significantly associated with poor prognosis and showed a strong trend toward being an independent prognostic factor for both OS ( P =0.051) and RFS ( P =0.061). Patients with DBDCs in the LRRC15 cancer+/stroma+ group had the worst RFS ( P =0.010*) and OS ( P =0.008*) by univariate analysis. LRRC15 overexpression was observed in a subset of DBDCs and was associated with pancreatic invasion and worse OS and RFS. Consequently, LRRC15 expression can be used as an indicator of poor survival in patients with DBDCs, particularly when both cancer cells and stromal expression are present.
The DESTINY-PanTumor02 phase II trial, showing a remarkable response to fam-trastuzumab deruxtecan-nxki (Enhertu), has triggered an increase in HER2 testing for drug eligibility. We evaluated HER2 immunohistochemical (IHC) and FISH testing results and the extent of Enhertu use in gynecologic tract clear cell carcinomas (GT-CCC) at a tertiary care center. Sixty-five GT-CCC with HER2 IHC testing performed at our institution (2018 to 2024) were identified: 49 ovarian (OCCC), 14 endometrial (ECCC), and 2 peritoneal. The 2018 ASCO/CAP criteria were used for HER2 scoring (the standard during the time frame of this study). Overall HER2 IHC scores were: 0 [n=12 (18.5%)], 1+ [n=9 (13.8%)], 2+ [n=40 (61.5%)], 3+ [n=4 (6.2%)]. FISH confirmed amplification in 22.9% OCCCs and 25% ECCCs (18.8% of IHC 2+ and all IHC 3+). Cases with unusual staining patterns (USP; strong nuclear and cytoplasmic) did not show FISH amplification. HER2 0/1+ and cases with USP were more frequent in biopsies (41.7%) and metastatic tumors (45.5%) compared with resections (30.2%) and primary sites (29.6%). Intratumoral heterogeneity was seen in 7.7% of cases. Among HER2 3+ cases, only 1 patient received anti-HER2 therapy (Herceptin followed by Enhertu) and had a mixed response. Of the HER2 2+ with positive FISH, 4 received anti-HER2 therapy, and only 1 patient had a good response. Based on current HER2 eligibility guidelines, our study shows that more than half of GT-CCC cases, that is, IHC HER2+, would be eligible for anti-HER2 therapy. However, few patients in our cohort received this therapy. Further studies are needed to evaluate the efficacy of anti-HER2 therapy for advanced/recurrent GT-CCC.
Assessment of HER2 overexpression and gene (ERBB2) amplification remains an essential predictive test that determines tailored breast cancer therapy. Based on institutional needs, we recently validated the VENTANA HER2 Dual ISH DNA Probe Cocktail assay (DISH). Validation included testing 61 retrospective breast cancers, followed by 40 prospective cases (parallel testing). There was 99% concordance for binary positive/negative status when correlated with immunohistochemistry, and 87% concordance for exact ISH category (groups 1 to 5). We designed an online tool for automatic calculation of ratios and group assignment, with prompts for additional counting when needed. During the first year, 1286 DISH assays were performed, with 2.9% initial assay failures requiring repeat. Based on conservative guidelines in the first year, we sent confirmatory fluorescence in situ hybridization (FISH) in 4% of cases; 9 cases (0.7%) had discordant DISH and FISH results, all of which were near a threshold (including "low amplified" results with HER2/CEP17 ≥2, average HER2/cell 4 to 6). The average turnaround time for HER2 DISH from ordering to finalization was 3.0 days, versus 4.8 days for FISH at our institution (37.5% improvement). We encountered occasional pitfalls, including zones lacking hybridization signals, and enhanced silver dust associated with anthracosis or tattoo pigment. We also observed differences across whole slide scanner platforms. HER2 DISH advantages included the ability of pathologists to directly score slides in correlation with morphology and immunohistochemistry, improved turnaround time, and greater automation for high-volume HER2 testing, as compared with FISH. In summary, we found HER2 DISH to be an accurate and practical alternative.
Keratoameloblastoma is a rare keratinizing neoplasia characterized by ameloblastic differentiation, which histopathologically resembles an odontogenic keratocyst. In view of its expansive growth, surgical enucleation and resection are alternatives for treating keratoameloblastoma. The objective was to report 2 cases of keratoameloblastoma, highlighting their clinical, radiologic, and histopathologic features, as well as the immunohistochemical profile of cytokeratins. Clinicopathologic findings were described, and the cases were submitted to immunohistochemistry for cytokeratins (CK) 6, 7, 8, 10, 13, 14, 17, 18, 19, and Ki-67. Both cases involved the jaws of adult men. Histologically, they showed fibrous stromal tissue permeated by keratinizing follicular cysts that formed central parakeratin plugs, features resembled ameloblastoma, and cystic formations resembled an odontogenic keratocyst. Variable positive labeling for all cytokeratins studied was observed, except for CK8 and CK18, which were negative. The Ki-67 proliferation index was low. Keratoameloblastoma is an expansive neoplasm with a low proliferation index. The cytokeratin profile generally follows that of ameloblastomas and odontogenic keratocysts. Both cases are under follow-up and show no recurrence after 4 years.
Various molecular pathways regulate oral squamous cell carcinoma (OSCC) progression, including epithelial-mesenchymal transition (EMT), which involves loss of epithelial adhesion, acquisition of mesenchymal traits, and upregulation of markers like Twist and Vimentin. Cancer-associated fibroblasts (CAFs) promote EMT through crosstalk with cancer cells. This study aimed to evaluate Twist and Vimentin IHC expression in OSCC and their correlation with tumor grade and lymph node (LN) metastasis. In addition, Twist and Vimentin mRNA levels were investigated in OSCC cells with and without fibroblasts. The study included 30 OSCC specimens (7 well-differentiated, 14 moderately differentiated, 9 poorly differentiated), with 12 showing LN metastasis. IHC staining for Twist and Vimentin was performed and analyzed. Gene expression was assessed by qRT-PCR in SCC-25, WI-38, and coculture. A Transwell migration assay was also conducted. Twist and Vimentin IRS showed significant correlation with OSCC grades ( P <0.05). Twist IRS had a strong correlation with LN involvement ( P <0.001), and Vimentin was significantly linked to LN metastasis ( P ≤0.001). Twist and Vimentin IRS were highly correlated ( P <0.001). Coculture for 7 days increased Twist and Vimentin expression compared with individual cell cultures. In the migration assay, the SCC + fibroblast group had significantly higher migration (4667.50±1042.24) than SCC alone (1136.67±137.79), P <0.001. Twist and Vimentin expressions as an assessment of EMT might offer better prognostic factors in OSCC and could be helpful detectors of subtle LN metastasis in OSCC.
Colorectal cancer (CRC) remains a leading cause of global cancer-related mortality. Cytidine triphosphate synthase 1 (CTPS1) is an essential enzyme for DNA synthesis and cell cycle progression. While CTPS1 has been implicated in the pathogenesis of various malignancies, its clinical significance in colorectal adenocarcinoma remains poorly defined. This study aimed to investigate the immunohistochemical (IHC) expression of CTPS1 in colorectal adenocarcinoma and evaluate its association with clinicopathological features and survival outcomes. CTPS1 expression was assessed via IHC in 168 colorectal adenocarcinoma specimens and 142 matched adjacent non-neoplastic tissues. Statistical associations with clinicopathological parameters were analyzed using χ 2 or Fisher exact tests. Progression-free survival (PFS) and disease-free survival (DFS) were estimated using the Kaplan-Meier method and compared via the log-rank test. Multivariate Cox proportional hazards regression was employed to identify independent prognostic factors. CTPS1 expression was significantly upregulated in tumour tissues compared with adjacent normal mucosa ( P <0.001). High CTPS1 expression was observed in 55.4% of tumor samples and significantly correlated with advanced T stage, TNM stage, and modified Dukes staging, as well as nodal involvement, distant metastasis, tumor recurrence, and elevated serum CEA levels. Furthermore, elevated CTPS1 was associated with aggressive histologic features, including higher grade, tumor budding, poorly differentiated clusters (PDCs), and tumor deposits. Both PFS and DFS were significantly shorter in patients with high CTPS1 expression ( P <0.001). Multivariate analysis confirmed that high CTPS1 expression, along with nodal status and tumor recurrence, was an independent prognostic factor for both PFS and DFS. Therefore, CTPS1 is a robust independent prognostic indicator and a marker of aggressive progression in colorectal adenocarcinoma. These findings suggest that CTPS1 is a promising biomarker for risk stratification and may guide clinical decision-making in the management of CRC.
BACKGROUND:The efficacy of endoscopic submucosal dissection (ESD) procedures and subsequent treatment is predominantly reliant on precise pathologic evaluation, intricately linked to specimen sampling and paraffin sectioning. Despite established guidelines in China for ESD specimen processing, the postsampling process remains intricate and error-prone. This study investigates the impact of various placement and labeling methods following ESD sampling on the quality of paraffin slides and the precision of pathologic diagnoses, with the ultimate goal of identifying the most effective approach. METHODS:We selected 45 ESD specimens and used 3 distinct postsampling placement and labeling methods: the conventional method, the sponge sandwich placement method, and the sponge interstitial vertical embedding method. Routine HE, IHC, and specific staining were performed to evaluate the effect. RESULTS:Our findings demonstrated that both the sponge sandwich placement and sponge interstitial vertical embedding methods resulted in superior HE preparation quality compared with the conventional method, with no discernible difference in HE preparation quality between the sponge sandwich and sponge interstitial vertical embedding methods. It was also verified by IHC and special staining. Nevertheless, the sponge sandwich placement method resulted in irregular marking of the dehydration box, making it challenging for technicians to determine the embedding direction of the specimens without a bulge or without remembering the embedding phenomenon. In contrast, the sponge interstitial vertical placement and labeling embedding method obviates the need to recognize the embedding direction of the specimen and tissues to be embedded; embedding is guided solely by the morphology and direction of the doctor-placed sponge. CONCLUSIONS:Based on our laboratory experience, we advocate for the sponge interstitial vertical embedding method.
Hans’ algorithm (HA) is the most frequently used surrogate biomarker scheme for subtyping Diffuse large B-cell lymphoma (DLBCL) by the cell-of-origin (COO) into GCB and non-GCB subtypes. The originally published positive and negative predictive value (PPV and NPV) against gene expression profiling (GEP) subtypes were less than perfect and were not fully reproducible in published literature. Furthermore, little is known about how the HA performs in clinical practice. The Canadian Association of Pathologists National Standard Committee for High Complexity Testing (CAP-ACP NSCHCT) initiated a Canada-wide project to assess the current diagnostic accuracy of the HA in clinical practice, harmonize the analytical phase of the IHC assays used for HA, and to optimize its overall diagnostic sensitivity and specificity against GEP subtypes. We divided a DLBCL cohort (n=96), where COO was defined by GEP (Lymph2CX, NanoString technologies) into training (TC, N=45) and validation cohort (VC, N=51) and tissue microarray (TMA)-TC and TMA-VC were constructed. Selected major Canadian laboratories applied their routine CD10, Bcl-6, and MUM1 IHC protocols and sent stained slides to the reference laboratory for review. The IHC protocols from laboratories were designated as “weak” (1/10), “moderate” (4/10), and “strong” (5/10) based on their overall analytical sensitivity. The results of the central review HA readouts were compared with GEP results. Furthermore, in TC, the original HA readout was modified to adjust the cutoff to overall IHC protocol sensitivity. The new readout criteria were also assessed in the VC set. The original HA readout showed good results against GEP for low sensitivity protocol only. For all other laboratories that had IHC protocols with moderate and high analytical sensitivity, a readout was adjusted to higher IHC protocol analytical sensitivity using a cutoff of >30% of >2+ staining intensity. This modification yielded significantly improved diagnostic accuracy against GEP even without any changes to the IHC protocols and was widely applicable to the range of analytical sensitivities of IHC protocols, which are currently in use. IHC biomarkers for HA can be highly accurate and harmonized across different laboratories for clinical application if the following criteria are met: (i) testing laboratories use standardized reference materials to set up and monitor analytical sensitivity, and (ii) the pathologist’s readout and cutoff are adjusted to the overall IHC protocol analytical sensitivity.
Understanding the pathogenesis of odontogenic cysts (OCs) may facilitate the development of alternative therapeutic strategies and improve patients' quality of life. Given calcitonin's role in regulating bone metabolism and its clinical applications in gnathic bone-destructive lesions, including OCs, this study assessed potential associations between CTR and the bone resorption markers receptor activator of nuclear factor kappa B ligand (RANKL) and tumor necrosis factor alpha (TNF-α) in OCs. Immunohistochemical analyses were performed on 20 radicular cysts (RCs), 20 radicular residual cysts (RRCs), and 27 dentigerous cysts (DCs). RANKL expression in the epithelial lining was significantly higher in RCs and RRCs compared with DCs ( p =0.039 and p =0.046, respectively). In RCs, significant positive correlations were found between epithelial RANKL and capsular CTR ( p =0.039), epithelial TNF-α and capsular TNF-α ( p =0.037), and epithelial TNF-α and capsular CTR ( p =0.005). In RRCs, epithelial RANKL correlated positively with epithelial TNF-α ( p =0.007) and capsular CTR correlated positively with capsular TNF-α ( p =0.041), whereas epithelial RANKL correlated negatively with capsular TNF-α ( p =0.009). In DCs, significant positive correlations were observed between epithelial and capsular RANKL ( p <0.001) and between epithelial and capsular TNF-α ( p =0.019). These findings suggest that CTR contributes to the pathogenesis of DCs, RCs, and RRCs, and highlight the involvement of RANKL and TNF-α in the biological behavior of these cysts. The interplay among these proteins may promote either osteolytic or osteogenic activity depending on the cystic microenvironment.
Follicular dendritic cell sarcoma (FDCS) is a rare malignant neoplasm commonly found in extranodal sites with unclear pathogenesis. Tumor cells typically exhibit a spindled morphology, whereas epithelioid morphology is rarely reported. Here, we have presented a rare biphasic FDCS with distinct immunophenotypic and molecular characteristics. A 63-year-old female presented with constipation and rectal bleeding. Imaging revealed an 11.4 cm lobulated enhancing soft tissue mass in the posterior pelvis. H&E sections revealed 2 sharply demarcated biphasic neoplastic populations: one population comprised spindled cells expressing CD21, CD23, CD35, clusterin, EMA, and D2-40; the other population consisted of epithelioid cells lacking CD21 and other FDC-associated markers except for focal weak clusterin expression. Both populations tested negative for CD163, CD68, S-100, langerin, CD1a, ALK-1, CD30, CD117, HMB45, Pan-CK, and EBER. The tumor was initially misdiagnosed as a collision (FDCS and perivascular epithelioid cell tumor) tumor. Molecular studies revealed a nearly identical mutational profile in both components confirming clonal identity and ruling out a composite tumor. In addition, low-level pathogenic mutations (variant allele frequency <10%) were found in GABRA6, ICOSLG, and VEGFA, alongside altered transcript expression in PDGFRB in both populations. Although no RNA fusions were detected, we demonstrated a significant increase in PDGFRB expression using the RNA Salah Targeted Expression panel, with a log 2 ratio > 2, indicating a more than 4-fold increase compared with a pooled normal control. Here, we have provided molecular characterization of biphasic FDCS. Prior such characterization seems to be unavailable in the literature.
