Breast cancers in monoallelic MUTYH germline mutation carriers have clinicopathological features overlapping with those in BRCA1 germline mutation carriers.

PURPOSE: Breast cancer patients referred to genetic counseling often undergo genetic testing with broad panels that include both breast cancer susceptibility genes as well as genes more specific for extramammary sites. As a result, patients are often incidentally found to have germline mutations in genes that are not necessarily related to breast cancer risk. One such gene is MUTYH. To understand the role MUTYH may play in breast cancer, the clinicopathological features of patients with monoallelic MUTYH germline mutation and breast cancer were examined. METHODS: The clinicopathological characteristics of the breast cancers from patients with monoallelic MUTYH mutation were compared to breast cancer patients with other germline mutations in known breast cancer susceptibility genes, including ATM, BRCA1/2, CHEK2, and PALB2. The breast cancer patients who received genetic counseling but tested negative for the aforementioned gene mutations were used as a control group. RESULTS: Histologic characteristics of the breast cancers arising in monoallelic MUTYH mutation carriers had significantly larger tumor size, higher tumor grade, and more high-risk biomarker profiles (i.e., Her2-positive and triple-negative) than breast cancer patients with susceptibility genes, except for BRCA1. MUTYH mutation carriers also showed a trend of more frequent intratumoral divergency in terms of tumor grade and biomarker profiles. CONCLUSION: Although germline monoallelic MUTYH mutation is not thought to confer a meaningfully increased risk of breast cancer development, it may contribute to pathological aggressiveness and diversity of breast cancers when they sporadically arise in MUTYH carriers.

Stress Keratin 17 Is a Predictive Biomarker Inversely Associated with Response to Immune Check-Point Blockade in Head and Neck Squamous Cell Carcinomas and Beyond.

Low response rates in immune check-point blockade (ICB)-treated head and neck squamous cell carcinoma (HNSCC) drive a critical need for robust, clinically validated predictive biomarkers. Our group previously showed that stress keratin 17 (CK17) suppresses macrophage-mediated CXCL9/CXCL10 chemokine signaling involved in attracting activated CD8+ T cells into tumors, correlating with decreased response rate to pembrolizumab-based therapy in a pilot cohort of ICB-treated HNSCC (n = 26). Here, we performed an expanded analysis of the predictive value of CK17 in ICB-treated HNSCC according to the REMARK criteria and investigated the gene expression profiles associated with high CK17 expression. Pretreatment samples from pembrolizumab-treated HNSCC patients were stained via immunohistochemistry using a CK17 monoclonal antibody (n = 48) and subjected to spatial transcriptomic profiling (n = 8). Our findings were validated in an independent retrospective cohort (n = 22). CK17 RNA expression in pembrolizumab-treated patients with various cancer types was investigated for predictive significance. Of the 48 patients (60% male, median age of 61.5 years), 21 (44%) were CK17 high, and 27 (56%) were CK17 low. A total of 17 patients (35%, 77% CK17 low) had disease control, while 31 patients (65%, 45% CK17 low) had progressive disease. High CK17 expression was associated with a lack of disease control (p = 0.037), shorter time to treatment failure (p = 0.025), and progression-free survival (PFS, p = 0.004), but not overall survival (OS, p = 0.06). A high CK17 expression was associated with lack of disease control in an independent validation cohort (p = 0.011). PD-L1 expression did not correlate with CK17 expression or clinical outcome. CK17 RNA expression was predictive of PFS and OS in 552 pembrolizumab-treated cancer patients. Our findings indicate that high CK17 expression may predict resistance to ICB in HNSCC patients and beyond.

Betapapillomaviruses in p16-Negative Vulvar Intraepithelial Lesions Associated with Squamous Cell Carcinoma.

Approximately 40% of vulvar squamous cell carcinoma (vSCC) cases are etiologically associated with high-risk human papillomaviruses (HPVs) of the alpha genera (α-HPV) that cause other anogenital cancers; however, the etiology of α-HPV-negative vSCC is poorly understood. HPVs of the beta genera (ß-HPV) are risk factors for cutaneous squamous cell carcinoma (cSCC) and may be related to carcinomas originating in other cutaneous sites such as the vulva. In this study, we investigate the presence of ß-HPVs, with an emphasis on p16-negative squamous lesions adjacent to vSCC. We subjected 28 vulvar squamous intraepithelial lesions adjacent to vSCC for comprehensive HPV genotyping, p16 and p53 immunohistochemistry, and consensus morphology review. Selected cases were subjected to qPCR and RNA in situ hybridization. Clinical data were obtained from medical records. ß-HPV DNA was detected in eight of ten p16-negative lesions and three of fourteen p16-positive high-grade squamous intraepithelial lesions. The HPV DNA loads in vulvar squamous intraepithelial lesions ranged between less than 1 HPV DNA copy per cell to more than 100 HPV DNA copies per cell. This is, to the best of our knowledge, the first report of the association of p16-negative vulvar intraepithelial squamous lesions with detection of ß-HPVs. These findings expand possible etiologic mechanisms that may contribute to p16-negative lesions of the vulva.

Grading of lung adenocarcinomas with simultaneous segmentation by artificial intelligence (GLASS-AI).

Preclinical genetically engineered mouse models (GEMMs) of lung adenocarcinoma are invaluable for investigating molecular drivers of tumor formation, progression, and therapeutic resistance. However, histological analysis of these GEMMs requires significant time and training to ensure accuracy and consistency. To achieve a more objective and standardized analysis, we used machine learning to create GLASS-AI, a histological image analysis tool that the broader cancer research community can utilize to grade, segment, and analyze tumors in preclinical models of lung adenocarcinoma. GLASS-AI demonstrates strong agreement with expert human raters while uncovering a significant degree of unreported intratumor heterogeneity. Integrating immunohistochemical staining with high-resolution grade analysis by GLASS-AI identified dysregulation of Mapk/Erk signaling in high-grade lung adenocarcinomas and locally advanced tumor regions. Our work demonstrates the benefit of employing GLASS-AI in preclinical lung adenocarcinoma models and the power of integrating machine learning and molecular biology techniques for studying the molecular pathways that underlie cancer progression.

A SOX10+/AR- immunoprofile may identify a subset of low positive ER carcinomas with a wider range of ER expression.

BACKGROUND: Invasive breast carcinomas (IBC) that strongly express SOX10 are almost always negative for androgen receptor (AR). Furthermore, this SOX10+/AR- subset of IBC is nearly always estrogen receptor and progesterone receptor negative (ER-/PR-), being most commonly seen in triple negative breast carcinomas (TNBC), but also in a small subset of HER2+/ER-/PR- IBC. Following our previous work demonstrating the expression of SOX10 in a subset of IBC with "low positive" ER expression (i.e. 1-10 % ER+ staining based on CAP guidelines, here referred to as "ER-low"), we sought to investigate the expression of both SOX10 and AR in a larger cohort of ER-low tumors. As our previous work also revealed occasional SOX10 expression in IBC with >10 % ER+ staining, we also included tumors with any percentage of ER staining, as long as the staining intensity was weak (this subset is referred to as "ER-weak"). METHODS: We screened cases of HER2-/ER+ IBC diagnosed at our institution over a 10 year period, identified both ER-low and ER-weak tumors and stained both groups with SOX10 and AR. RESULTS: Strong SOX10 expression was seen in 12/25 (48 %) ER-low tumors and 13/24 (54 %) ER-weak tumors. ER staining in the SOX10+ subset of ER-weak tumors ranged from 15 %-80 % (median 25 %). As expected, AR was negative in all but 1 of the SOX10+ tumors in both groups. While case numbers in these groups were too small for a meaningful statistical analysis, we did note that all SOX10+/AR- tumors within both the ER-low and ER-weak groups were histologic grade 3. CONCLUSION: The presence of a SOX10+/AR- profile in a significant subset of ER-low tumors confirms the findings of our previous work and provides further support for the proposed functionally ER negative status of this group. Furthermore, the fact that the same SOX10+/AR- profile is seen in a roughly equal subset of ER-weak tumors suggests that a wider range of ER staining may be acceptable as "low positive" in SOX10+/AR- tumors, as long as the ER staining is of weak intensity. However, given the small number of cases in this single institution study, we emphasize the need for larger studies to establish the biological and clinical significance of this tumor subset.

Adenosquamous carcinoma in situ of the anus: a case series.

While human papillomavirus (HPV)-associated adenocarcinoma of the anus resembling endocervical adenocarcinoma has recently been described, anal adenocarcinoma in situ/AIS has not. Moreover, to the best of our knowledge, truly biphasic anal adenosquamous carcinoma in situ (ADSQ-IS) is essentially non-existent in the literature. Here, we report four cases of anal ADSQ-IS including one with associated invasive adenosquamous carcinoma. Histologically, all cases of ADSQ-IS showed a basal/peripheral population of stratified, p40-positive dysplastic squamous cells adjacent to luminal, columnar, p40-negative dysplastic glandular cells, bearing a striking resemblance to the normal anal transitional epithelium. Both lesional components were diffusely and strongly positive for p16 and positive for high-risk HPV by RNA in situ hybridization. These cases expand the morphological spectrum of high-risk HPV-associated pre-invasive lesions and underscore the plasticity of HPV-associated neoplasia.

Stress Keratin 17 Expression in Head and Neck Cancer Contributes to Immune Evasion and Resistance to Immune-Checkpoint Blockade.

PURPOSE: We investigated whether in human head and neck squamous cell carcinoma (HNSCC) high levels of expression of stress keratin 17 (K17) are associated with poor survival and resistance to immunotherapy. EXPERIMENTAL DESIGN: We investigated the role of K17 in regulating both the tumor microenvironment and immune responsiveness of HNSCC using a syngeneic mouse HNSCC model, MOC2. MOC2 gives rise to immunologically cold tumors that are resistant to immune-checkpoint blockade (ICB). We engineered multiple, independent K17 knockout (KO) MOC2 cell lines and monitored their growth and response to ICB. We also measured K17 expression in human HNSCC of patients undergoing ICB. RESULTS: MOC2 tumors were found to express K17 at high levels. When knocked out for K17 (K17KO MOC2), these cells formed tumors that grew slowly or spontaneously regressed and had a high CD8+ T-cell infiltrate in immunocompetent syngeneic C57BL/6 mice compared with parental MOC2 tumors. This phenotype was reversed when we depleted mice for T cells. Whereas parental MOC2 tumors were resistant to ICB treatment, K17KO MOC2 tumors that did not spontaneously regress were eliminated upon ICB treatment. In a cohort of patients with HNSCC receiving pembrolizumab, high K17 expression correlated with poor response. Single-cell RNA-sequencing analysis revealed broad differences in the immune landscape of K17KO MOC2 tumors compared with parental MOC2 tumors, including differences in multiple lymphoid and myeloid cell types. CONCLUSIONS: We demonstrate that K17 expression in HNSCC contributes to immune evasion and resistance to ICB treatment by broadly altering immune landscapes of tumors.

Pulmonary Alveolar Proteinosis Refractory to Plasmapheresis and Rituximab despite GM-CSF Antibody Reduction.

We share our experience of a patient with pulmonary alveolar proteinosis who was refractory to plasmapheresis and rituximab despite a significant reduction in the offending antibody. He presented with shortness of breath, fevers, chills, and sweats for 4 months. He was diagnosed with autoimmune PAP based on typical radiology findings, bronchoalveolar fluid analysis, and elevated anti-GM-CSF levels. Given his limited improvement with whole lung lavage and inhaled GM-CSF therapy, he underwent two series of plasmapheresis. Series one was 5 procedures in 6 days, and series two was 5 procedures in 9 days followed by rituximab. These did not appear to provide any lasting clinical benefit in the year after plasmapheresis despite a marked decrease in serum anti-GM-CSF levels. However, about a year after plasmapheresis, he went into remission and has not required any treatment.

Macrophage-Derived Cholesterol Contributes to Therapeutic Resistance in Prostate Cancer.

Castration-resistant prostate cancer (CRPC) is a lethal stage of disease in which androgen receptor (AR) signaling is persistent despite androgen deprivation therapy (ADT). Most studies have focused on investigating cell-autonomous alterations in CRPC, while the contributions of the tumor microenvironment are less well understood. Here we sought to determine the role of tumor-associated macrophages in CRPC, based upon their role in cancer progression and therapeutic resistance. In a syngeneic model that reflected the mutational landscape of CRPC, macrophage depletion resulted in a reduced transcriptional signature for steroid and bile acid synthesis, indicating potential perturbation of cholesterol metabolism. As cholesterol is the precursor of the five major types of steroid hormones, we hypothesized that macrophages were regulating androgen biosynthesis within the prostate tumor microenvironment. Macrophage depletion reduced androgen levels within prostate tumors and restricted AR nuclear localization in vitro and in vivo. Macrophages were also cholesterol-rich and were able to transfer cholesterol to tumor cells in vitro. AR nuclear translocation was inhibited by activation of liver X receptor (LXR)-ß, the master regulator of cholesterol homeostasis. Consistent with these data, macrophage depletion extended survival during ADT and the presence of macrophages correlated with therapeutic resistance in patient-derived explants. Taken together, these findings support the therapeutic targeting of macrophages in CRPC. SIGNIFICANCE: These results suggest that macrophage-targeted therapies can be combined with androgen deprivation therapy to treat patients with prostate cancer by limiting cholesterol bioavailability and the production of intratumoral androgens.See related commentary by Al-Janabi and Lewis, p. 5399.