Tumor-associated macrophages (TAMs) can influence ovarian cancer growth, migration, and metastasis, but the detailed mechanisms underlying ovarian cancer metastasis remain unclear. Here, we have shown a strong correlation between TAM-associated spheroids and the clinical pathology of ovarian cancer. Further, we have determined that TAMs promote spheroid formation and tumor growth at early stages of transcoelomic metastasis in an established mouse model for epithelial ovarian cancer. M2 macrophage–like TAMs were localized in the center of spheroids and secreted EGF, which upregulated α_Mβ₂ integrin on TAMs and ICAM-1 on tumor cells to promote association between tumor cells and TAM. Moreover, EGF secreted by TAMs activated EGFR on tumor cells, which in turn upregulated VEGF/VEGFR signaling in surrounding tumor cells to support tumor cell proliferation and migration. Pharmacological blockade of EGFR or antibody neutralization of ICAM-1 in TAMs blunted spheroid formation and ovarian cancer progression in mouse models. These findings suggest that EGF secreted from TAMs plays a critical role in promoting early transcoelomic metastasis of ovarian cancer. As transcoelomic metastasis is also associated with many other cancers, such as pancreatic and colon cancers, our findings uncover a mechanism for TAM-mediated spheroid formation and provide a potential target for the treatment of ovarian cancer and other transcoelomic metastatic cancers.

Mismatch repair–deficient (MMRd) cancers have varied responses to immune-checkpoint blockade (ICB). We conducted a phase II clinical trial of the PD-1 inhibitor pembrolizumab in 24 patients with MMRd endometrial cancer (NCT02899793). Patients with mutational MMRd tumors (6 patients) had higher response rates and longer survival than those with epigenetic MMRd tumors (18 patients). Mutation burden was higher in tumors with mutational MMRd compared with epigenetic MMRd; however, within each category of MMRd, mutation burden was not correlated with ICB response. Pretreatment JAK1 mutations were not associated with primary resistance to pembrolizumab. Longitudinal single-cell RNA-seq of circulating immune cells revealed contrasting modes of antitumor immunity for mutational versus epigenetic MMRd cancers. Whereas effector CD8+ T cells correlated with regression of mutational MMRd tumors, activated CD16+ NK cells were associated with ICB-responsive epigenetic MMRd tumors. These data highlight the interplay between tumor-intrinsic and tumor-extrinsic factors that influence ICB response. Significance: The molecular mechanism of MMRd is associated with response to anti–PD-1 immunotherapy in endometrial carcinoma. Tumors with epigenetic MMRd or mutational MMRd are correlated with NK cell or CD8+ T cell–driven immunity, respectively. Classifying tumors by the mechanism of MMRd may inform clinical decision-making regarding cancer immunotherapy. This article is highlighted in the In This Issue feature, p. 247

Background: We evaluated the expression of human trophoblastic cell-surface marker (Trop-2) and the potential of hRS7 - a humanized monoclonal anti-Trop-2 antibody - as a therapeutic strategy against treatment-refractory human uterine (UMMT) and ovarian (OMMT) carcinosarcoma cell lines. Materials and methods: Trop-2 expression was evaluated by immunohistochemistry (IHC) in paraffin-embedded tumor tissues, by real-time polymerase-chain-reaction (RT-PCR) and flow-cytometry in cell lines. Sensitivity to hRS7 antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity was tested using 5-hour chromium-release assays against UMMT and OMMT cells. Results: Trop-2 expression was elevated in 9 of 26 (35%) UMMT and 8 of 14 (57%) OMMT tissues tested by IHC. Positivity for Trop-2 mRNA by RT-PCR and surface expression by flow cytometry were detected in 2 of 4 cell lines, with high positivity noted in OMMT-ARK-2. OMMT-ARK-2 was highly sensitive to hRS7 ADCC (range: 34.7-41.0%; P < 0.001) with negligible cytotoxicity seen in the absence of hRS7 or in the presence of control antibody (range: 1.1-2.5%). Human IgG did not significantly inhibit ADCC while human complement increased, hRS7-mediated-cytotoxicity against OMMT-ARK-2. Conclusion: Trop-2 is overexpressed in a proportion of UMMT and OMMT, and hRS7 may represent a novel, potentially highly effective treatment option for patients with treatment-refractory carcinosarcomas overexpressing Trop-2.

Background: Cervical cancer continues to be an important worldwide health problem for women. Up to 35% of patients who are diagnosed with and appropriately treated for cervical cancer will recur and treatment results are poor for recurrent disease. Given these sobering statistics, development of novel therapies for cervical cancer remains a high priority. We evaluated the expression of Tissue Factor (TF) in cervical cancer and the potential of hI-con1, an antibody-like-molecule targeted against TF, as a novel form of immunotherapy against multiple primary cervical carcinoma cell lines with squamous- and adenocarcinoma histology.Methods: Because TF is a transmembrane receptor for coagulation factor VII/VIIa (fVII), in this study we evaluated thein vitroexpression of TF in cervical carcinoma cell lines by immunohistochemistry (IHC), real time-PCR (qRT-PCR) and flow cytometry. Sensitivity to hI-con1-dependent cell-mediated-cytotoxicity (IDCC) was evaluated in 5-hrs-⁵¹chromium-release-assays against cervical cancer cell linesin vitro.Results: Cytoplasmic and/or membrane TF expression was observed in 8 out of 8 (100%) of the tumor tissues tested by IHC and in 100% (11 out of 11) of the cervical carcinoma cell lines tested by real-time-PCR and flow cytometry but not in normal cervical keratinocytes (p= 0.0023 qRT-PCR;p= 0.0042 flow cytometry). All primary cervical cancer cell lines tested overexpressing TF, regardless of their histology, were highly sensitive to IDCC (mean killing ± SD, 56.2% ± 15.9%, range, 32.4%-76.9%,p< 0.001), while negligible cytotoxicity was seen in the absence of hI-con1 or in the presence of rituximab-control-antibody. Low doses of interleukin-2 further increased the cytotoxic effect induced by hI-con1 (p= 0.025) while human serum did not significantly decrease IDCC against cervical cancer cell lines (p= 0.597).Conclusions: TF is highly expressed in squamous and adenocarcinoma of the uterine cervix. hI-con1 induces strong cytotoxicity against primary cervical cancer cell lines overexpressing TF and may represent a novel therapeutic agent for the treatment of cervical cancer refractory to standard treatment modalities.