The study of the impact of physical forces and on cells has emerged as a fertile field of investigation. Applications in oncology are especially transformative since tumor stiffness was found associated with fundamental processes such as tumorigenicity, disease progression, and resistance to therapy. We present an integrated atomic force microscopy-statistical modeling and machine learning approach in colon cancer to link clinical and phenotypical parameters with local maps of tissue stiffness. Statistical modeling found both known associations, such as with age or tumor stage, but also novel associations, such as with RAS mutations, tumor left-/right-colon localization, and DNA repair deficiencies (microsatellite instabilities). Machine learning was able to infer clinical parameters from stiffness data. This work establishes a computational framework to build global models integrating all the available clinical parameters and assess their relevance with respect to stiffness, while they are usually explored separately. Similarly, we established spatial statistics techniques to interpolate and model the topographical information embedded in local stiffness maps.

HER2-low and -ultralow breast cancer have recently emerged as distinct theranostic subcategories within the HER2 spectrum, prompting reassessment of traditional HER2-negative immunohistochemistry scores (0, 1+ , and 2+ without amplification). This study reclassifies, according to this new categorization, a cohort of 367 patients who have never received chemotherapy and have non-metastatic triple-negative breast cancer (TNBC). We evaluated its association with their clinicopathological features and prognosis. HER2 0 tumors were reclassified as HER2-null (no staining) or HER2-ultralow (≤10

This study evaluated circulating mRNAs (B2M, TIMP-1, CLU, SERPINE1, GAL3, and S100A9) as potential biomarkers for colorectal cancer (CRC). Plasma levels were measured in CRC patients (stages I-IV, n = 178) and healthy individuals (HIs, n = 171). B2M, TIMP-1, CLU, and S100A9 mRNA levels were significantly elevated in CRC patients vs. HIs. B2M differed only in stage IV, while TIMP-1, CLU, and S100A9 showed significance across all stages except I. A composite index, I-BTC, was developed using B2M, TIMP-1, and CLU via logistic regression. I-BTC improved discrimination between HIs and CRC patients, even at stage I (p = 0.001), with stronger significance in later stages (p ≤ 0.0001). These results validate analytical robustness of the method and highlight its diagnostic potential including for early-stage CRC through specific mRNAs combinations.

Preclinical and clinical studies increasingly show that the immune response plays a major role in radiotherapy. Here, we investigated the role of major histocompatibility complex class I (MHC-I) molecules recognized by cytotoxic CD8+ T cells in the response to radiopharmaceutical therapy (RPT). Methods: Two murine melanoma cell lines that express low and high MHC-I levels (B16F10 and B16K1, respectively) were grafted in syngeneic or athymic and nude mice, and the response to a single injection of [225Ac]Ac-DOTA-TA99 monoclonal antibodies (9.25 or 18.5 kBq) was assessed and related to dosimetry. For clinical relevance, MHC-I expression was determined in samples from patients with well-differentiated, iodine-avid metastatic thyroid cancer and well-differentiated grade 2 mid-gut neuroendocrine tumors. Results: RPT efficacy was enhanced by T-cell presence and MHC-I expression. In mice harboring B16F10 and B16K1 melanoma tumors, RPT showed a stronger antitumor effect in C57BL/6J (immunocompetent) animals than in athymic and nude (immunodeficient) animals, suggesting a crucial role of T-cell-mediated immune responses. Moreover, the response to irradiation was the same in B16K1 MHC-Ihigh tumors with a low absorbed dose of α-RPT and in B16F10 MHC-Ilow tumors with a 4 times higher absorbed dose. These results indicate that CD8+ T cells can counterbalance low tumor irradiation. Conversely, delivering high absorbed doses leads to side effects and seems to prevent immune system activation, thereby not taking advantage of these mechanisms. Our results also indicate that MHC-I can be used as a predictive biomarker of RPT response in lesions receiving low absorbed doses and that RPT treatment regimens should be reconsidered in the function of the MHC-I expression level. Conclusion: This study shows that MHC-I expression can predict RPT immunostimulatory effects. This is relevant in metastatic disease where lesions in the same patient can receive very low or very high absorbed doses.

The involvement of calcium signaling in tumor progression has been well documented in the literature. In particular, the calcium channel TRPV6 has been identified as a key player in the physiopathology of solid tumors. At the transcriptomic level, TRPV6 is overexpressed in many cancers such as prostate, pancreatic and ovarian cancers underscoring its potential as a new therapeutic target. While some TRPV6-targeting antagonistic peptides have reached clinical stage, no antibody candidate is currently in development. Leveraging its phage display technology and unique proprietary antibody libraries, Mabqi (France), in collaboration with SATT Nord and PhyCell laboratory (France), has discovered and characterized a first-in-class human anti-TRPV6 antibody "20H3” with high clinical potential. A comprehensive series of vitro and vivo preclinical studies demonstrated the safety profile, efficacy and clinical relevance of 20H3 antibody, as a new candidate for the treatment of prostate cancer. In vitro studies demonstrated the high affinity and specificity of 20H3 antibody against TRPV6 target. Exploration of antigen-antibody interaction was performed through epitope and paratope mapping and antagonistic activity of 20H3 antibody was validated via calcium flux modulation assays. The excellent developability properties were also demonstrated through thermostability, aggregation and stability assays. In vivo, the 20H3 safety profile was confirmed in mice model. After repeated doses up to 64 mg/kg, no effect on mice body weight and no sign of toxicity in main organs collected were detected. The antitumoral potential of 20H3 antibody was evaluated in three vivo cancer models. As initial positioning is prostate cancer indication, efficacy studies in two xenografted prostate models (LNCaP and VCaP) were performed. In both models, specific tumor targeting and tumor penetration were confirmed and a strong antitumoral efficacy was demonstrated at 4-8 mg/kg with a tumor growth inhibition superior to 60 % and an increased mice survival of 62 %. Interestingly a strong efficacy was also shown in MCA205 sarcoma model. To further elucidate antibody’s mode of action, a comparison between Fc-WT and Fc-silencing format was carried out in immunocompetent and immunodeficient mice models. All together, these results demonstrated that antitumor efficacy is mediated by both paratopic region and Fc region of the antibody that potentializes the effect of the treatment. Finally, the 20H3 clinical relevance was demonstrated by immunohistochemistry studies with positive immunoreactivity in a large proportion of prostate cancer patient samples. The 20H3 antibody is the first anti-TRPV6 antibody under development, with a strong potential to advance rapidly into clinic. The CMC process of 20H3 drug candidate is planned in 2025 and Phase Ia clinical trial is expected to start in early 2027. Lindsay B. Alcaraz, Vincent Roux-Portalez, Aurélien Haustrate, Gautier Robin, Alexia Parmentier, Clément Cordier, Florence Boissière-Michot, Amélie Gudin-de-Vallerin, Evelyne Lopez-Crapez, Gaelle Fromont-Hankard, Tristan Mangeat, Margaux Maurel, Marianne Le Gall, Thierry Chardès, Bruno Robert, Yoann Sottejeau, Diego Tosi, Natacha Prevarskaya, V'yacheslav Lehen'kyi, Bernard Pau, Johanna Marines. First-in-class anti-TRPV6 antibody as a new therapeutic agent in cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4770.

BACKGROUND:Triplet chemotherapy plus cetuximab showed promising results in phase II trials in unsystematically selected RAS population. We evaluated FOLFIRINOX+cetuximab efficacy as first-line treatment in extended RAS wild-type metastatic colorectal cancer (mCRC) patients. METHODS:We retrospectively analyzed patients treated with FOLFIRINOX+cetuximab, using data from clinical trials and real-life practice. Extended mutation analysis was performed when RAS/BRAF status was unavailable. The primary endpoint was progression-free survival (PFS). RESULTS:Seventy patients (61.4 % male, median age 58.7 years) were analyzed. Eighty percent had left-sided mCRC and 97.1 % had liver metastases. Median PFS and overall survival (OS) were 13.3 and 48.5 months, respectively. The objective response rate was 85.7 %, with 20 % complete response. Primary tumor location did not affect OS and PFS. BRAF wild-type patients (n = 65) had longer PFS (13.3 vs. 6.0 months; p = 0.005) and OS (50.1 vs. 21.2 months; p = 0.007) than BRAF mutated patients (n = 5, including four BRAFV600E). Median OS was significantly longer in resected patients (n = 39, 55.1 vs. 30.7 months; p = 0.030). Main toxicities were diarrhea (31.4 %) and neutropenia (21.4 %). CONCLUSION:FOLFIRINOX+cetuximab provides good PFS, high response rate and prolonged disease control in initially unresectable extended RAS wild-type mCRC. This combination is particularly interesting for selected patients with liver-limited disease eligible to secondary resection.

Epithelial ovarian cancer (EOC) is the leading cause of death from gynecological cancers in Western countries. High-Grade Serous Ovarian Carcinoma (HGSOC) accounts for 60–70% of EOC and is the most aggressive subtype. Reduced PTPN13 expression levels have been previously correlated with worse prognosis in HGSOC. However, PTPN13’s exact role and mechanism of action in these tumors remained to be investigated. To elucidate PTPN13’s role in HGSOC aggressiveness, we used isogenic PTPN13-overexpressing clones of the OVCAR-8 cell line, which poorly expresses PTPN13, and also PTPN13 CRISPR/Cas9-mediated knockout/knockdown clones of the KURAMOCHI cell line, which strongly expresses PTPN13. We investigated their migratory and invasive capacity using a wound healing assay, their mesenchymal-epithelial transition (EMT) status using microscopy and RT-qPCR, and their sensitivity to chemotherapeutic drugs used for HGSOC. We found that (i) PTPN13 knockout/knockdown increased migration and invasion in KURAMOCHI cells that also displayed a more mesenchymal phenotype and increased expression of the SLUG, SNAIL, ZEB-1, and ZEB-2 EMT master genes; and (ii) PTPN13 expression increased the platinum sensitivity of HGSOC cells. These results suggest that PTPN13 might be a predictive marker of response to platinum salts in HGSOC.

Background Colorectal cancer (CRC) patients have a better prognosis if metastases are resectable. Initially, unresectable liver-only metastases can be converted to resectable with chemotherapy plus a targeted therapy. We assessed which of chemotherapy doublet (2-CTx) or triplet (3-CTx), combined with targeted therapy by RAS status, would be better in this setting. Methods PRODIGE 14 was an open-label, multicenter, randomised Phase 2 trial. CRC patients with initially defined unresectable liver-only metastases received either, 2-CTx (FOLFOX or FOLFIRI) or 3-CTx (FOLFIRINOX), plus bevacizumab/cetuximab by RAS status. The primary endpoint was to increase the R0/R1 liver-resection rate from 50 to 70% with the 3-CTx. Results Patients ( n = 256) were mainly men with an ECOG PS of 0, and a median age of 60 years. In total, 109 patients (42.6%) had RAS-mutated tumours. After a median follow-up of 45.6 months, the R0/R1 liver-resection rate was 56.9% (95% CI: 48–66) with the 3-CTx versus 48.4% (95% CI: 39–57) with the 2-CTx ( P = 0.17). Median overall survival was 43.4 months with 3-CTx versus 40 months with 2-CTx. Conclusion We failed to increase from 50 to 70% the R0/R1 liver-resection rate with the use of 3-CTx combined with bevacizumab or cetuximab by RAS status in CRC patients with initially unresectable liver metastases.

Besides the standard parameters used for colorectal cancer (CRC) management, new features are needed in clinical practice to improve progression-free and overall survival. In some cancers, the microenvironment mechanical properties can contribute to cancer progression and metastasis formation, or constitute a physical barrier for drug penetration or immune cell infiltration. These mechanical properties remain poorly known for colon tissues. Using a multidisciplinary approach including clinical data, physics and geostatistics, we characterized the stiffness of healthy and malignant colon specimens. For this purpose, we analyzed a prospective cohort of 18 patients with untreated colon adenocarcinoma using atomic force microscopy to generate micrometer-scale mechanical maps. We characterized the stiffness of normal epithelium samples taken far away or close to the tumor area and selected tumor tissue areas. These data showed that normal epithelium was softer than tumors. In tumors, stroma areas were stiffer than malignant epithelial cell areas. Among the clinical parameters, tumor left location, higher stage, and RAS mutations were associated with increased tissue stiffness. Thus, in patients with CRC, measuring tumor tissue rigidity may have a translational value and an impact on patient care.

Background: Triple-negative breast cancers (TNBCs) have a worse prognosis, but might respond to immunotherapies. Macrophages are plastic cells that can adopt various phenotypes and functions. Although they are a major immune population in TNBCs, the relationship between tumor-associated macrophages (TAMs) and TNBC progression has been rarely explored, with controversial results. Methods: We evaluated the prognostic impact of TAMs, quantified by immunohistochemistry with anti-CD68, -IRF8, -CD163, and -CD206 antibodies, in a well-described cohort of 285 patients with non-metastatic TNBC. Results: CD68 (p = 0.008), IRF8 (p = 0.001), and CD163 (p < 0.001) expression positively correlated with higher tumor grade, while CD206 was associated with smaller tumor size (p < 0.001). All macrophage markers were associated with higher tumor-infiltrating lymphocyte numbers and PD-L1 expression. Univariate survival analyses reported a significant positive correlation between CD163+ or CD206+ TAMs and relapse-free survival (respectively: HR = 0.52 [0.28–0.97], p = 0.027, and HR = 0.51 [0.31–0.82], p = 0.005), and between CD206+ TAMs and overall survival (HR = 0.54 [0.35–0.83], p = 0.005). In multivariate analysis, there was a trend for an association between CD206+ TAMs and relapse-free survival (HR = 0.63 [0.33–1.04], p = 0.073). Conclusions: These data suggest that CD206 expression defines a TAM subpopulation potentially associated with favorable outcomes in patients with TNBC. CD206 expression might identify an immune TNBC subgroup with specific therapeutic options.

Cancer stem cells (CSCs) are a small but critical cell population for cancer biology since they display inherent resistance to standard therapies and give rise to metastases. Despite accruing evidence establishing a link between deregulation of epitranscriptome-related players and tumorigenic process, the role of messenger RNA (mRNA) modifications in the regulation of CSC properties remains poorly understood. Here, we show that the cytoplasmic pool of fat mass and obesity-associated protein (FTO) impedes CSC abilities in colorectal cancer through its N 6 ,2’-O-dimethyladenosine (m 6 A m ) demethylase activity. While m 6 A m is strategically located next to the m 7 G-mRNA cap, its biological function is not well understood and has not been addressed in cancer. Low FTO expression in patient-derived cell lines elevates m 6 A m level in mRNA which results in enhanced in vivo tumorigenicity and chemoresistance. Inhibition of the nuclear m 6 A m methyltransferase, PCIF1/CAPAM, fully reverses this phenotype, stressing the role of m 6 A m modification in stem-like properties acquisition. FTO-mediated regulation of m 6 A m marking constitutes a reversible pathway controlling CSC abilities. Altogether, our findings bring to light the first biological function of the m 6 A m modification and its potential adverse consequences for colorectal cancer management.

Microsatellite instability (MSI) is related to the alteration of mismatch repair (MMR) genes and plays a key role in colorectal cancer (CRC) pathogenesis. We previously reported that the transcription factor Nuclear Receptor Interacting Protein 1 (NRIP1) is involved in sporadic intestinal tumorigenesis. The aim of this study was to decipher its role in MSI CRC. By using different mouse models and engineered cell lines, we demonstrated that NRIP1 increased MSH2 and MSH6 MMR gene transcription and mRNA/protein levels. In human CRC cells, NRIP1 expression was associated with decreased MSI and the hypermutator phenotype, and with resistance to chemotherapy drugs. Using a cohort of 194 CRC patients, we detected in 22% of the cases a MSI-induced frameshift mutation in the NRIP1 coding sequence. This genetic alteration generates a truncated protein with a dominant negative activity that increased human CRC cell proliferation and impaired the regulation of MSH2 and MSH6 gene expression. Moreover, the NRIP1 mutant correlated with a decreased overall survival of patients with advanced CRC, especially when MLH1-deficient. By decreasing the expression of MSH2 and MSH6 gene expression, the NRIP1 variant may amplify MLH1-dependent CRC progression and behave as a new prognostic marker of advanced MSI CRC.

The prognostic impact of the different tumor-infiltrating lymphocyte (TIL) subpopulations in solid cancers is still debated. Here, we investigated the clinicopathological correlates and prognostic impact of TILs, particularly of γδ T cells, in 162 patients with triple-negative breast cancer (TNBC). A high γδ T cell density (>6.625 γδ T cells/mm2) was associated with younger age (p = 0.008), higher tumor histological grade (p = 0.002), adjuvant chemotherapy (p = 0.010), BRCA1 promoter methylation (p = 0.010), TIL density (p < 0.001), and PD-L1 (p < 0.001) and PD-1 expression (p = 0.040). In multivariate analyses, γδ T cell infiltration (cutoff = 6.625 γδ T cells/mm2) was an independent prognostic factor (5-year relapse-free survival: 63.3% vs. 89.8%, p = 0.027; 5-year overall survival: 73.8% vs. 89.9%, p = 0.031, for low vs. high infiltration). This prognostic impact varied according to the tumor PIK3CA mutational status. High γδ T cell infiltration was associated with better survival in patients with PIK3CA wild-type tumors, but the difference was not significant in the subgroup with PIK3CA-mutated tumors. Altogether, these data suggest that high γδ T cell infiltrate is correlated with immune infiltration and might represent a candidate prognostic tool in patients with TNBC.

Background Data regarding the prognostic value of programmed cell death ligand 1 (PD-L1) expression on circulating tumor cells (CTCs) are lacking. However, CTCs could represent an alternative approach to serial biopsies, allowing real-time monitoring of cancer phenotype. Methods We evaluated, in a dedicated prospective clinical trial, the clinicopathological correlations and prognostic value of PD-L1(+)-CTCs in 72 patients with metastatic breast cancer (MBC). Results Eighteen of 56 patients with available archival tissue presented at least one positive (≥1%) PD-L1 tumor sample. Baseline CTCs and PD-L1(+)-CTCs were detected in 57 (79.2%) and 26 (36.1%) patients. No significant correlation was found between PD-L1 tumors and CTC expression. In univariate analysis, triple negative (TN) phenotype, number of metastatic treatments, >2 metastatic sites, ≥5 CTCs and PD-L1(+)-CTCs were significantly associated with progression-free survival, while tissue PD-L1 expression was not. In multivariate analysis, TN phenotype, number of metastatic treatments and of metastatic sites were the only 3 variables independently associated with progression-free survival. Progesterone receptor negativity, TN phenotype, >2 metastatic sites and ≥5 CTCs were significantly associated with overall survival in univariate analysis. In multivariable analysis, TN phenotype and >2 metastatic sites were the only 2 independent variables. Conclusions Unlike PD-L1(+)-tumor, PD-L1(+)-CTCs correlate to survival in MBC. Reappraisal of the role of PD-L1 expression by tumor tissue and by CTCs under anti-PD-1/PD-L1 treatment is necessary to evaluate its predictive value and potential role as a stratifying factor in strategies and trials for MBC patients with MBC. Clinical trial registration NCT02866149

No treatment was available for patients with RAS-mutated (RASmt) metastatic colorectal cancer (mCRC) refractory to standard chemotherapies at the time of the study. A total of 173 patients with RASmt mCRC were randomized between NEXIRI (IRI + NEX), irinotecan (IRI), and sorafenib (NEX). The 2-month nonprogression disease rate was 52.6% [95% CI: 39%-66%], 21.4% [10%-33%], and 19.3% [9%-30%], respectively. NEXIRI combination can delay progression of RASmt mCRC. Background: No treatment option was available for patients with RAS-mutated (RASmt) metastatic colorectal cancer (mCRC) who progress after standard combined chemotherapies at the time of the study. After promising results in phase II, the aim of the present NEXIRI-2/PRODIGE 27 trial was to assess the 2-month non-progression rate for sorafenib (NEX) plus irinotecan (IRI), that is, NEXIRI, treatment. Methods: Patients with RASmt mCRC after failure of oxaliplatin, IRI, fluoropyrimidines, and bevacizumab were randomized between NEXIRI (IRI 120-180 mg/m(2) intravenous, D1 = D15 plus oral NEX 400 mg twice a day) versus IRI (180 mg/m(2)) versus NEX. Primary endpoint was the 2-month non-progression rate. Secondary endpoints included progression-free and overall survival (PFS and OS), safety, and germline cyclin D1 (CCND1) rs9344 polymorphisms analyses. Results: A total of 173 patients were included, 59 in NEXIRI, 57 in IRI, and 57 in NEX arms. The 2-month non-progression rate was 52.6% (95% confidence interval [CI]: 39%-66%), 21.4% (10%-33%), and 19.3% (9%-30%) for NEXIRI, IRI, and NEX. Median PFS was 3.6 (95% CI: 2-4.2), 1.7 (1.7-1.8), and 2 (1.8-2.3) months and the median OS was 7.2 (5.8-9.4), 6.3 (4.8-8), and 5.6 (3.9-7.7) months for NEXIRI, IRI, and NEX, respectively. For NEXIRI rs9344CCND1 A/A genotype patients, OS was 19.6 months (95% CI: 4.8enot reached). Main grade 3 toxicities included neutropenia, febrile neutropenia, diarrhea, hand-foot syndrome, and hypertension. Conclusions: In patients with RASmt mCRC who progressed after standard combined chemotherapies, the results of 2-month non-progression rate and median PFS in the NEXIRI arm were in favor of an increase of the time before progression. (C) 2020 Elsevier Inc. All rights reserved.

In a previous phase II study (THERAPY), cetuximab and trastuzumab combination, as second-line after progression with gemcitabine, showed disease stabilization in 27% of 33 patients with pancreatic carcinoma. In the present phase II multicenter study, we assessed the efficacy and tolerance of gemcitabine, trastuzumab plus erlotinib as first-line treatment of metastatic pancreatic cancer. The primary endpoint was disease control rate (DCR, RECIST v.1); secondary endpoints were progression-free (PFS), overall (OS) survival and toxicity (NCI-CTCAE v3.0). Ancillary study addressed the predictive value of both EGFR/HER2 expression andKRASmutational status. Sixty-three patients from four centers were included (62 evaluable for toxicity, 59 for efficacy), median age was 62 years (35-77), 59.7% men. The median treatment duration was 16.1 weeks (2.1-61). Eleven patients (19%) reported a partial tumor response, and 33 (56%) disease stabilization. DCR was 74.6% (95%CI: 61.8-85.0; 44/59 patients). After a median follow-up of 23.3 months (0.6-23.6), median PFS was 3.5 months (95%CI: 2.4-3.8) and median OS 7.9 months (95%CI: 5.1-10.2). PFS was significantly longer in patients with grade >= 2 cutaneous toxicities vs patients with grade 0-1 toxicities (HR = 0.55, 95%CI: 0.33-0.92,P= .020). Expression of EGFR and HER2 was correlated with PFS and OS in multivariate analysis; HER2 expression was correlated with the tumor response. Main severe toxicities were neutropenia (32%), cutaneous rash (37%) and thrombosis/embolisms (35.5%). This triplet combination is effective in terms of disease control, PFS and OS, and acceptable for safety. A larger study to investigate this combination compared to the standard regimen should be discussed.

γδ T-cells contribute to the immune response against many tumor types through their direct cytolytic functions and their capacity to recruit and regulate the biological functions of other immune cells. As potent effectors of the anti-tumor immune response, they are considered an attractive therapeutic target for immunotherapies, but their presence and abundance in the tumor microenvironment are not routinely assessed in patients with cancer. Here, we validated an antibody for immunohistochemistry analysis that specifically detects all γδ T-cell subpopulations in healthy tissues and in the microenvironment of different cancer types. Tissue microarray analysis of breast, colon, ovarian, and pancreatic tumors showed that γδ T-cell density varies among cancer types. Moreover, the abundance of γδ tumor-infiltrating lymphocytes was variably associated with the outcome depending on the cancer type, suggesting that γδ T-cell recruitment is influenced by the context. These findings also suggest that γδ T-cell detection and analysis might represent a new and interesting diagnostic or prognostic marker.

gamma delta T cells contribute to the immune response against many cancers, notably through their powerful effector functions that lead to the elimination of tumor cells and the recruitment of other immune cells. However, their presence in the tumor microenvironment has been associated with poor prognosis in breast, colon, and pancreatic cancer, suggesting that gamma delta T cells may also display pro-tumor activities. Here, we identified in blood from healthy donors a subpopulation of V delta 1T cells that represents around 20% of the whole V delta 1 population, expresses CD73, and displays immunosuppressive phenotype and functions (i.e., production of immunosuppressive molecules, such as IL-10, adenosine, and the chemotactic factor IL-8, and inhibition of alpha beta T cell proliferation). We then found that in human breast tumors, gamma delta T cells were present particularly in late stage breast cancer samples, and that similar to 20% of tumor-infiltrating gamma delta T cells expressed CD73. Taken together, these results suggest that regulatory gamma delta T cells are present in the breast cancer microenvironment and may display immunosuppressive functions through the production of immunosuppressive molecules, such as IL-10, IL-8, and adenosine, thus promoting tumor growth.

The aberrant hypermethylation of BRCA1 promoter CpG islands induces the decreased expression of BRCA1 (Breast Cancer 1) protein. It can be detected in sporadic breast cancer without BRCA1 pathogenic variants, particularly in triple-negative breast cancers (TNBC). We investigated BRCA1 hypermethylation status (by methylation-specific polymerase chain reaction (MS-PCR) and MassARRAY® assays), and BRCA1 protein expression using immunohistochemistry (IHC), and their clinicopathological significance in 248 chemotherapy-naïve TNBC samples. Fifty-five tumors (22%) exhibited BRCA1 promoter hypermethylation, with a high concordance rate between MS-PCR and MassARRAY® results. Promoter hypermethylation was associated with reduced IHC BRCA1 protein expression (p = 0.005), and expression of Programmed death-ligand 1 protein (PD-L1) by tumor and immune cells (p = 0.03 and 0.011, respectively). A trend was found between promoter hypermethylation and basal marker staining (p = 0.058), and between BRCA1 expression and a basal-like phenotype. In multivariate analysis, relapse-free survival was significantly associated with N stage, adjuvant chemotherapy, and histological subtype. Overall survival was significantly associated with T and N stage, histology, and adjuvant chemotherapy. In addition, patients with tumors harboring BRCA1 promoter hypermethylation derived the most benefit from adjuvant chemotherapy. In conclusion, BRCA1 promoter hypermethylation is associated with TNBC sensitivity to adjuvant chemotherapy, basal-like features and PD-L1 expression. BRCA1 IHC expression is not a good surrogate marker for promoter hypermethylation and is not independently associated with prognosis. Association between promoter hypermethylation and sensitivity to Poly(ADP-ribose) polymerase PARP inhibitors needs to be evaluated in a specific series of patients.