In metastatic cancer, the role of heterogeneity at the tumor-immune microenvironment, its molecular underpinnings and clinical relevance remain largely unexplored. To understand tumor-immune dynamics at baseline and upon chemotherapy treatment, we performed unbiased pathway and cell type-specific immunogenomics analysis of treatment-naive (38 5 samples from 8 patients) and paired chemotherapy treated (80 paired samples from 40 patients) high-grade serous ovarian cancer (HGSOC) samples. Whole transcriptome analysis and imagebased quantification of T cells from treatment-naive tumors revealed ubiquitous variability in immune signaling and distinct immune microenvironments co-existing within the same individuals and within tumor deposits at diagnosis. To systematically explore cell type composition of the tumor microenvironment using bulk mRNA, we derived consensus immune and stromal cell gene signatures by intersecting state-of-the-art deconvolution methods, providing improved accuracy and sensitivity when compared to HGSOC immunostaining and leukocyte methylation data sets. Cell-type deconvolution and pathway analyses revealed that Myc and Wnt signaling associate with immune cell exclusion in untreated HGSOC. To evaluate the effect of chemotherapy on the intrinsic tumor-immune heterogeneity, we compared sitematched and site-unmatched tumors before and after neoadjuvant chemotherapy.Transcriptomic and T-cell receptor sequencing analyses showed that site-matched samples had increased cytotoxic immune activation and oligoclonal expansion of T cells after chemotherapy, which was not seen in site-unmatched samples where heterogeneity could not be accounted for. These results demonstrate that the tumor-immune interface in advanced HGSOC is intrinsically heterogeneous, and thus requires site-specific analysis to reliably unmask the impact of therapy on the tumor-immune microenvironment..

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Highlights Neoadjuvant chemotherapy induces heterogeneous changes in the tumor microenvironment. Macrophages are a significant component of the TME PD-L1 expression enriched in a subset of patients. Alteration in T cell ratios after chemotherapy indicate patient subsets favorable to checkpoint modulation in the recurrent setting.

Leydig cell hyperplasia (LCH) is a rare cause of hyperandrogenism that has been described only in case reports. The cases presented herein contrast the traditional presentation of LCH with an affected asymptomatic individual. The first case involves a 74-year-old woman presenting with symptomatic hyperandrogenism, whose symptoms resolved after bilateral salpingo-oophorectomy (BSO). The second patient presented with postmenopausal bleeding and an abdominal mass. Following total abdominal hysterectomy (TAH) and BSO, pathology showed ovarian LCH with concomitant endometrial cancer. The diagnosis of LCH is complex and requires careful investigation of many differential diagnoses. Incidentally discovered LCH may shed light on evolution and disease progression. Cases of LCH found in the setting of endometrial pathology may have implications on other states of testosterone excess.