Abstract Introduction: Tumor-associated macrophages (TAMs) are key regulators of the tumor immune microenvironment (TIME). Macrophage class A scavenger receptors (SR-A) modulate macrophage activation and polarization, and increased SR-A-positive TAMs are associated with poor outcomes in several cancers, including breast cancer. We previously showed that SR-A engagement skews macrophages toward an immunosuppressive phenotype, suggesting that SR-A blockade may reprogram the TIME and enhance antitumor immunity. In this study, we tested whether SR-A blockade reprograms the TIME and limits tumor progression in tumor-bearing mice. Methods: EO771 cancer cells were injected into mammary fat pads of syngeneic mice to establish breast tumors. Tumor-bearing mice were treated with an SR-A antagonist or a control, and then CD45+ tumor-infiltrating cells were isolated for single-cell RNA sequencing. In separate cohorts, SR-A blockade was combined with CD137-targeted activation, and mice were euthanized when tumors reached the predefined tumor endpoint (volume ≥ 1.5 cm3). In parallel, mice were treated with the appropriate controls for both SR-A antagonist and CD137 activation. Tumor volume, time to the tumor endpoint, and the presence of lung metastases were determined. Mice showing complete tumor regression were rechallenged by assessing tumor growth following the injection of EO771 cells into the contralateral mammary fat pad. Results: Monotherapy with the SR-A antagonist did not significantly alter primary tumor growth. However, single-cell RNA-seq of CD45+ tumor-infiltrating cells indicated a shift in the polarization of tumor-associated macrophages toward an immunostimulatory, antigen-presenting phenotype, characterized by the upregulation of MHC class II molecules. Further, there was an increase in a cytotoxic T-cell subset characterized by high expression of the CD137 co-stimulatory receptor. Extending these results, we evaluated the effect of combining the SR-A antagonist with targeted CD137 activation. Treating tumor-bearing mice with the combination of SR-A antagonist and CD137 activation significantly inhibited both tumor growth and the proportion of mice that developed lung metastases compared to control-treated mice. Moreover, a subset of treated mice achieved complete tumor regression and rejected subsequent tumor rechallenge, consistent with the generation of durable systemic antitumor immune memory. Conclusions: Inhibiting SR-A-dependent interactions reprograms macrophages toward a tumor-hostile, antigen-presenting phenotype, enhances cytotoxic T-cell responses, and synergizes with CD137-targeted activation. Thus, SR-A-blocking strategies may improve the efficacy of co-stimulatory receptor agonists by conditioning the TIME. Citation Format: Steven R. Post, Fariba Jousheghany, Thomas J. Kelly, Charles M. Quick, Behjatolah M. Karbassi. SR-A antagonism remodels the myeloid population of tumor immune microenvironment, expands CD8-positive T cells, and enhances antitumor efficacy in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2908.

Hypertrophic lichen sclerosus (HLS) is poorly characterized. A recent study described an atypical form of LS (p53 wild type) with a CK17/D2-40 immunohistochemical profile intermediate between classic LS and differentiated vulvar intraepithelial neoplasia (dVIN). Our study aims to characterize HLS through IHC and molecular profiling to determine if it is a classic or atypical LS lesion. We reviewed HLS diagnosed in 12 biopsies (2014 to 2025) and 5 resections for vulvar squamous cell carcinoma (vSCC) (1998 to 2015) from our institution (mean patient age 59; range: 37 to 97). We defined HLS by nonexophytic acanthosis, hyperkeratosis +/- parakeratosis, granular layer retention, irregular dermal-epidermal junction, lack of severe basal layer atypia, homogenization of the superficial dermis, and +/- lichenoid inflammatory infiltrate. In the 5 resections, CK17 expression was suprabasal in 4 (80%) and superficial in 1 (20%) of HLS adjacent to vSCC. D2-40 intensity was moderate in all 5 (100%). All 5 vSCC were p16-/p53 aberrant with intense D2-40 expression and showed diffuse CK17 in 4 (80%) and suprabasal staining in 1 (20%). All 12 HLS biopsies were p16-; 7 (58%) were p53 wild type and 5 (42%) were aberrant. Seven (58%) showed CK17 suprabasal staining; 5 (42%) were diffuse. D2-40 intensity ranged from absent (1/12; 8%) to faint (3/12; 25%) to moderate (3/12; 25%) to intense (5/12; 42%). Frequently altered genes were SDHA (3/6; 50%) and TP53 (2/6; 33%). HLS shows neither the classic morphology of LS nor dVIN but can be p53 aberrant/mutant. Because of its CK17/D2-40 immunophenotype, it should be considered as atypical LS.

T cells are pivotal to cancer immunotherapy, yet chemotherapy may erode their fitness. Using a single-cell technique, we show that exposure to two widely used chemotherapeutic agents, 5-FU (5-fluorouracil) and cisplatin, induces non-synonymous mitochondrial DNA (mtDNA) mutations in T cells. Notably, nearly all detected mtDNA mutations are transition mutations. Like the effects observed in genomic DNA mutations, the impacts of mtDNA mutations in T cells appear to be random. Some T cells with mtDNA mutations concentrate in clusters associated with gene markers, while others do not. Additionally, several mtDNA mutations are found in the fraction of treated T cells with low mitochondrial activity, suggesting their potential effect on mitochondrial function. Importantly, mtDNA mutations are detected in tumor-infiltrating T cells from patients with colorectal cancer who received chemotherapy. Our findings uncover an unappreciated consequence of chemotherapy on T cell mitochondria, and these results raise concerns about administering immunotherapy and chemotherapy concurrently.

Hypertrophic lichen sclerosus (HLS) is poorly characterized. A recent study described an atypical form of LS (p53 wild type) with a CK17/D2-40 immunohistochemical profile intermediate between classic LS and differentiated vulvar intraepithelial neoplasia (dVIN). Our study aims to characterize HLS through IHC and molecular profiling to determine if it is a classic or atypical LS lesion. We reviewed HLS diagnosed in 12 biopsies (2014 to 2025) and 5 resections for vulvar squamous cell carcinoma (vSCC) (1998 to 2015) from our institution (mean patient age 59; range: 37 to 97). We defined HLS by nonexophytic acanthosis, hyperkeratosis +/− parakeratosis, granular layer retention, irregular dermal-epidermal junction, lack of severe basal layer atypia, homogenization of the superficial dermis, and +/− lichenoid inflammatory infiltrate. In the 5 resections, CK17 expression was suprabasal in 4 (80%) and superficial in 1 (20%) of HLS adjacent to vSCC. D2-40 intensity was moderate in all 5 (100%). All 5 vSCC were p16-/p53 aberrant with intense D2-40 expression and showed diffuse CK17 in 4 (80%) and suprabasal staining in 1 (20%). All 12 HLS biopsies were p16-; 7 (58%) were p53 wild type and 5 (42%) were aberrant. Seven (58%) showed CK17 suprabasal staining; 5 (42%) were diffuse. D2-40 intensity ranged from absent (1/12; 8%) to faint (3/12; 25%) to moderate (3/12; 25%) to intense (5/12; 42%). Frequently altered genes were SDHA (3/6; 50%) and TP53 (2/6; 33%). HLS shows neither the classic morphology of LS nor dVIN but can be p53 aberrant/mutant. Because of its CK17/D2-40 immunophenotype, it should be considered as atypical LS.

In recent years, rare fibrosarcoma-like tumors have been identified in the gynecologic tract characterized by variable CD34 and S-100 positivity and recurrent tyrosine kinase gene fusions in many cases. We identified 17 of these tumors by searching for gynecologic sarcomas expressing S-100 and/or CD34 and supplementing these with cases contributed by collaborating institutions. Tumors involved the uterine cervix (n=11), uterine corpus (n=4), and vagina (n=2). Patients ranged from 28 to 64 (median: 50) years. Fifteen tumors showed overlapping morphologic features including haphazard or fascicular growth of relatively monotonous spindled to ovoid cells with minimal to moderate cytoplasm. Tyrosine kinase gene fusions were identified in 9 tumors, including NTRK fusions in 6 and COL1A1::PDGFB in 3 tumors. Oncogenic variants in ERBB2/ERBB3 were identified in 6 additional tumors. These two subgroups showed distinct immunohistochemical profiles, with all tyrosine kinase fusion-positive tumors being CD34 positive, variably S-100 positive, and SOX10 negative. In contrast, the ERBB-altered tumors were CD34 negative and diffusely positive for S-100 and SOX10. The remaining 2 tumors showed morphologic and immunohistochemical overlap with the tyrosine kinase fusion-positive sarcomas; one was negative for fusion or sequence variants, and sequencing failed in the other. In conclusion, most fibrosarcoma-like tumors of the gynecologic tract are defined by either tyrosine kinase fusions or ERBB2/3 mutations. Immunohistochemistry can be used to predict these subgroups to guide confirmatory genetic testing and targeted therapies.

Extramammary Paget disease (EMPD) is characterized by intraepithelial neoplastic glandular cells with hyperchromatic nuclei and abundant pale, mucin-rich cytoplasm. One of our authors previously reported 3 cases of primary EMPD exhibiting an unusual morphology characterized by darker pagetoid cells ("Dark Paget"). Our study aims to identify additional cases to further describe this unique presentation. Our database was queried for vulvar EMPD (2018-2025). We defined "Dark Paget" cells as smaller in size with an increased nuclear to cytoplasmic ratio, a striking absence of abundant pale cytoplasm, and hyperchromatic nuclei with irregular contours. Support was provided by staining with CK7 (and additional stains as applicable) for all patients. Patient age, clinical presentation and treatment were recorded. A total of 96 vulvar EMPD specimens were identified, of which 10 cases from 3 patients (age range: 34-84 yr, mean: 72) fit the morphologic criteria for "Dark Paget." EMPD was clinically suspected in all (10/10, 100%) cases; all 10 (100%) represented a recurrence and shared similar prior treatment modalities. On low-power magnification, "Dark Paget" mimicked an HPV-associated squamous intraepithelial lesion in 6 (60%) and differentiated vulvar intraepithelial neoplasia in 4 (40%) cases. This unusual presentation of vulvar EMPD, termed "Dark Paget," represents a diagnostic pitfall, potentially leading to delay in proper diagnosis and management. Awareness of this subtle presentation and careful histopathologic evaluation, combined with a low threshold for ancillary staining, is essential to avoid misdiagnosis. A potential association between patients with recurrent disease, "Dark Paget" morphology and prior treatment modalities requires further investigation.

Polypoid endometriosis is a rare variant characterized by mass-forming endometriosis, often mimicking malignancy. This report describes the case of a postmenopausal woman who presented with an incidental complex adnexal mass and elevated tumor markers. She underwent bilateral salpingo-oophorectomy and mass removal. Frozen section suggested endometriosis with possible serous borderline tumor, prompting staging. Final pathology revealed polypoid endometriosis with areas of endometrioid intraepithelial neoplasia. Polypoid endometriosis may present as a postmenopausal pelvic mass with elevated tumor markers and can contain endometrioid intraepithelial neoplasia.

Squamous cell carcinoma of the vulva (vSCC) is currently categorized either as human papillomavirus (HPV) associated or independent. Immunohistochemical stains, p16 INK4a (p16) and p53 are helpful biomarkers to support the designation of vSCC into 1 of the 3 tumor pathways: (1) HPV-associated, (2) HPV-independent, TP53 mutant, or (3) HPV-independent, TP53 wild type. Recently, a framework of p53 expression patterns in vSCC was proposed. In this international and multi-institutional study, we evaluated the interrater agreement for p53 and p16 and tumor pathway classification in a cohort of 50 invasive vSCC across a variety of practice settings (private practice, academic medicine) and levels of expertise (trainees, gynecologic pathologists, dermatopathologists, private practice pathologists). Our study shows that the overall interrater agreement for the interpretation of p16 in vSCC is strong to near perfect, while the agreement for p53 and tumor pathway assignment is overall moderate. Interrater agreement for p53 and tumor pathway is higher (strong) in the academic practice setting. Pathologists without gynecologic subspecialty expertise benefited the most from a brief educational module, which fostered a better understanding and improved comfort level with the p16/p53 stain interpretation and tumor pathway designation in the diagnosis of vSCC. Some interpretative challenges remain, particularly in regard to select p53 patterns and high-risk HPV-in situ hybridization utilization, warranting additional research.

The widespread use of progestin therapy for endometrial precancer/cancer introduces complexities in the interpretation of pathology specimens. This chapter delves into the nuanced morphological changes triggered by progestin therapy in both neoplastic and non-neoplastic endometrial tissues. Understanding these changes is crucial for accurate pathological diagnosis, thereby enabling clinicians to make strategic treatment decisions. The primary focus lies in discerning progestin-treated atypical endometrial hyperplasia/endometrioid intraepithelial neoplasia (AEH/EIN), where the detection of residual or recurrent disease often involves significant interobserver variability and diagnostic challenges. Recent progress made in the utility biomarkers as adjuncts in the diagnosis of endometrial precancers, particularly in the context of post-progestin treated samples, is outlined. The utility of a PAX-2, PTEN, β-catenin immunohistochemistry panel, and the importance of uniform diagnostic reporting are discussed. The chapter amalgamates the existing literature, presents an effective diagnostic algorithm, and offers guidance for assessing endometrial biopsies in this setting. Lastly, it highlights recent insights into the molecular mechanisms that are thought to underlie the influences of progestins on normal and neoplastic endometrium, as well as in instances of progestin resistance.

PURPOSE A non-surgical alternative for treating cervical intraepithelial neoplasia (CIN) 2/3 is an unmet need due to a risk of cervical incompetency. METHODS PepCan consists of four human papillomavirus (HPV) type 16 E6 peptides and a Candida skin testing reagent (adjuvant). In this randomized, double-blind Phase 2 study, women with biopsy-confirmed CIN2/3 were treated with PepCan or Candida at one to one ratio. Four intradermal injections were given every 3 weeks, with observation visits at 6 and 12 months post-vaccination. Quadrant biopsies were performed at the 12-month visit, and those whose lesions regressed to no CIN were considered to be complete responders. Regression rates of each treatment group were compared to that of a historical placebo group. RESULTS With the intention-to-treat analysis, PepCan (n=39) showed 30.8% efficacy (95% confidence interval [CI], 17 to 47.6; p=0.25) while Candida (n=42) demonstrated 47.6% efficacy (95% CI, 32 to 63.6; p<0.001). Likewise, with the per-protocol analysis, PepCan (n=24) showed 45.8% efficacy (95% CI, 25.6 to 67.2; p=0.08) and Candida (n=29) showed 62.1% efficacy (95% CI, 42.3 to 79.3; p<0.001). There was no difference between efficacy of PepCan and Candida . No dose-limiting toxicity was observed. HPV-specific T cell responses were elicited in both groups. Vaccine-induced HPV-specific CD4 and CD8 T cells were present in cervix regardless of histological response. Single-cell RNA-seq revealed increased expression of granzymes, CCR5, and EOMES in HPV-specific CD8-positive T cells of a histological responder, compared to non-responders. Six cytokines (CCL4, CCL5, interleukin-9, lymphotoxin-α, platelet-derived growth factor-ββ, tumor growth factor-β1) were significantly decreased in both Candida recipients and histological responders suggesting that Candida may possibly exert its anti-tumor effects through these systemic mediators. CONCLUSIONS Candida may be effective in inducing histological regression. PepCan and Candida treatments are safe. Candida should be evaluated in a Phase 3 trial as a potential new treatment for CIN2/3. ### Competing Interest Statement Mayumi Nakagawa is one of the inventors named in patents and patent applications for PepCan and Candida . Other authors declare no potential conflicts of interest. ### Clinical Trial NCT02481414 ### Funding Statement This study was supported by grants from the National Institutes of Health (R01CA143130 and UL1 TR003107). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee/IRB of University of Arkansas for Medical Sciences gave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced are available online at GenBank.

The conventional dualistic model of endometrial cancer (types I and II) has been the mainstay in clinical practice for decades. However, recent advances show that this model does not capture the heterogeneity of endometrial cancer. As a result, there has been a strong demand for a more comprehensive understanding of the molecular and genetic mechanisms underlying endometrial carcinogenesis. This chapter aims to provide a comprehensive overview of the most recent advances in endometrial carcinogenesis with potential clinical implications for diagnosis and management. In particular, we focus on molecular-based classifications of endometrial carcinoma, which have emerged as promising tools for predicting patient prognosis and survival. We also propose a unified pathologic classification for intraepithelial endometrial neoplasia that could facilitate a more accurate diagnosis and risk stratification for patients.

Frozen section analysis of the gynecologic tract is a complex task due to the number of organs, tumors, and entities involved. Correlation with the indication for surgery as well as knowledge of what specific information that the surgeon seeks must be understood for each consultation. Often, the specimen is complex, with many parts, requiring extensive pre-sectioning dissection and gross evaluation. Careful execution of this step is paramount for a successful intraoperative consultation. Awareness of the importance of a thorough gross evaluation, careful selection of samples, and the numerous histologic features associated with this endeavor is a must. Often, selection of multiple fragments of tissue for frozen analysis can help to identify subtle histologic clues upon microscopy. Routinely, two to three sections per specimen may be submitted. This chapter acts to serve as a quick reference to some of the more common epidemiologic, gross, and histologic features of some of the more common entities encountered in intraoperative consultation of the female reproductive system.

Endometriosis is a chronic, estrogen-dependent, inflammatory disorder that affects ~10% of reproductive-aged women. The condition, characterized by the presence of endometrial glands and stroma outside of the uterine cavity, is multifactorial and highly recurrent, and causes chronic pelvic pain and other morbidities (e.g., depression, asthma, and migraines) that significantly diminish quality of life. The disease is linked to immune dysfunctions, infertility, and increased risk for ovarian and other (e.g., breast and endometrial) cancers. Its pathophysiology is poorly understood but is considered to have a significant genetic component and may involve abnormal endometrial epithelial progenitors. The histological diagnosis of endometriosis may be compromised by the cellular complexity and heterogeneity of the endometriotic foci which can manifest a spectrum of lesions with distinct and atypical features of stromal and glandular components. Moreover, signs and symptoms of endometriosis remain nonspecific, and a current lack of predictive noninvasive biomarkers precludes early diagnosis. This chapter aims to provide current understanding of the etiology, pathogenesis, and clinicopathologic features of endometriosis, and how emerging information from state-of-the-art technologies may be exploited for the diagnosis, management of symptoms, and therapy in women with this condition.

Giant cell tumors are neoplasms that usually occur in the long bones of young adults. They can rarely present in the soft tissue and may display malignant behavior. Giant cell malignancies have previously been reported as tumors primary of the uterus but are exceptionally rare. Although uncommon, it is important to consider when a neoplasm with osteoclast-like giant cells is encountered. In this report, we describe a 70-year-old female patient with an unremarkable past history who presented with an enlarged uterus. Transvaginal ultrasound demonstrated multiple fibroids and a thickened endometrium. A biopsy diagnosis of a highgrade sarcoma was rendered and further refined in the surgical resection as malignant giant cell tumor of the uterus. In this case report, we describe the findings of this case and discuss the differential diagnosis of this entity.

The protein basic helix-loop-helix family member e40 (BHLHE40) is a transcription factor recently emerged as a key regulator of host immunity to infections, autoimmune diseases and cancer. In this study, we investigated the role of Bhlhe40 in protective T cell responses to the intracellular bacterium Chlamydia in the female reproductive tract (FRT). Mice deficient in Bhlhe40 exhibited severe defects in their ability to control Chlamydia muridarum shedding from the FRT. The heightened bacterial burdens in Bhlhe40 -/- mice correlated with a marked increase in IL-10-producing T regulatory type 1 (Tr1) cells and decreased polyfunctional CD4 T cells co-producing IFN-γ, IL-17A and GM-CSF. Genetic ablation of IL-10 or functional blockade of IL-10R increased CD4 T cell polyfunctionality and partially rescued the defects in bacterial control in Bhlhe40 -/- mice. Using single-cell RNA sequencing coupled with TCR profiling, we detected a significant enrichment of stem-like T cell signatures in Bhlhe40 -deficient CD4 T cells, whereas WT CD4 T cells were further down on the differentiation trajectory with distinct effector functions beyond IFN-γ production by Th1 cells. Altogether, we identified Bhlhe40 as a key molecular driver of CD4 T cell differentiation and polyfunctional responses in the FRT against Chlamydia .

Cannabidiol (CBD) has gained widespread popularity; however, its pharmacological and toxicological profiles in the context of human genetic diversity remain largely unexplored. Here, we investigated the variability in metabolism and toxicity of CBD-rich cannabis extract (CRCE) in genetically diverse mouse models: C57BL/6J, B6C3F1/J, and NZO/HlLtJ strains. Mice received a single dose of CRCE containing 57.9% CBD at dosages of 0, 246, 738, and 2460 mg/kg of CBD. At 24 h after treatment, no appreciable histomorphological changes were detected in the liver. Plasma bilirubin levels increased markedly in all strains at the highest CBD dose. Mice in all treatment groups displayed significant but distinct increases in ALT and AST levels. While B6C3F1/J and NZO/ HlLtJ mice had negligible plasma CBD levels at 738 mg/kg, C57BL/6J mice exhibited levels exceeding 7000 ng/ mL. At 2460 mg/kg, high CBD concentrations were found in B6C3F1/J and C57BL/6J mice, but markedly lower levels were seen in NZO/HlLtJ mice. Gene expression profiling showed significant increases in Cyp2b10 across all strains but varying responses in Cyp1a1 expression, indicating strain-specific CYP dysregulation. Genetically diverse mice exhibited differential pharmacological and toxicological responses to CRCE, suggesting a high potential for inter-individual variability in the pharmacology and toxicology of CBD in humans.

High-grade neuroendocrine cervical cancers (NETc) are exceedingly rare, highly aggressive tumors. We analyzed 64 NETc tumor samples by whole-exome sequencing (WES). Human papillomavirus DNA was detected in 65.6% (42/64) of the tumors. Recurrent mutations were identified in PIK3CA, KMT2D/MLL2, K-RAS, ARID1A, NOTCH2, and RPL10. The top mutated genes included RB1, ARID1A, PTEN, KMT2D / MLL2, and WDFY3, a gene not yet implicated in NETc. Somatic CNV analysis identified two copy number gains (3q27.1 and 19q13.12) and five copy number losses (1p36.21/5q31.3/6p22.2/9q21.11/11p15.5). Also, gene fusions affecting the ACLY-CRHR1 and PVT1-MYC genes were identified in one of the eight samples subjected to RNA sequencing. To resolve evolutionary history, multiregion WES in NETc admixed with adenocarcinoma cells was performed (i.e., mixed-NETc). Phylogenetic analysis of mixed-NETc demonstrated that adenocarcinoma and neuroendocrine elements derive from a common precursor with mutations typical of adenocarcinomas. Over one-third (22/64) of NETc demonstrated a mutator phenotype of C > T at CpG consistent with deficiencies in MBD4 , a member of the base excision repair (BER) pathway. Mutations in the PI3K/AMPK pathways were identified in 49/64 samples. We used two patient-derived-xenografts (PDX) (i.e., NET19 and NET21) to evaluate the activity of pan-HER (afatinib), PIK3CA (copanlisib), and ATR (elimusertib) inhibitors, alone and in combination. PDXs harboring alterations in the ERBB2/PI3K/AKT/mTOR/ATR pathway were sensitive to afatinib, copanlisib, and elimusertib ( P < 0.001 vs. controls). However, combinations of copanlisib/afatinib and copanlisib/elimusertib were significantly more effective in controlling NETc tumor growth. These findings define the genetic landscape of NETc and suggest that a large subset of these highly lethal malignancies might benefit from existing targeted therapies.