Tumor-associated macrophage expression of PD-L1 in implants of high grade serous ovarian carcinoma: A comparison of matched primary and metastatic tumors.

OBJECTIVE: Data on PD-L1 expression in high grade serous ovarian carcinoma (HGSOC) is mixed. Some studies report robust tumor staining and others identify expression limited to tumor-associated macrophages (TAM). TAM PD-L1 expression is induced in HGSOC metastatic implants from patients who have undergone chemotherapy. However, it is unclear whether TAM acquisition of PD-L1 plays a role in treatment naïve tumors. We investigated PD-L1 expression in primary ovarian tumors and matched metastatic implants from predominantly treatment-naïve HGSOC. METHODS: Sixty one primary HGSOC were evaluated with PD-L1 and CD68 IHC: 40 on TMA and 21 on whole section. Whole section cases were matched to a metastatic implant. TAM were delineated by CD68. Membranous PD-L1 staining was scored separately for tumor cells and TAM. RESULTS: Eight percent of primary HGSOC demonstrated PD-L1 expression. In contrast, 74% showed PD-L1+ TAM. In the 16 treatment naïve cases, 13 (81.3%) demonstrated fidelity in intratumoral PD-L1 expression between the primary and metastatic site. Of the 21 matched pairs, only one case (4.8%) did not exhibit PD-L1 positive TAM in the metastatic implant and 19 (90.5%) showed fidelity across both locations. Intratumoral and immune infiltrate PD-L1 expression was not different in cases who received neoadjuvant chemotherapy compared to treatment naïve cases. CONCLUSIONS: PD-L1+ TAM are common in both primary and metastatic HGSOC however tumoral PD-L1 staining is rare. There was high fidelity of PD-L1 expression when comparing primary tumors and metastatic implants in treatment naïve specimens. Clinical trials are needed to determine whether tumor-associated staining correlates with clinical response to PD-1/PD-L1 inhibition.

Pure Apocrine Carcinomas Represent a Clinicopathologically Distinct Androgen Receptor-Positive Subset of Triple-Negative Breast Cancers.

Apocrine carcinomas comprise ∼1% of all breast cancers and are characterized by large cells bearing abundant eosinophilic granular cytoplasm, round nuclei, and prominent nucleoli. They are typically estrogen receptor/progesterone receptor/HER2 negative, making them unresponsive to typical hormonal or HER2-based chemotherapy. However, this subtype of triple-negative breast cancers expresses androgen receptor (AR), a feature not shared by most nonapocrine triple-negative cancers (NA-TNCs). AR therefore represents a potential diagnostic tool and therapeutic target for apocrine breast carcinoma. All pure apocrine carcinomas diagnosed during a 10-year period were reviewed, and clinicopathologic characteristics were compared with a control group of 26 NA-TNC cases. Twenty apocrine carcinomas were identified (∼0.8% of all breast cancers). The mean age at diagnosis was 69.3 years for apocrine carcinomas and 56.7 years for NA-TNC. All apocrine carcinomas and no NA-TNC were AR positive. The proportions of apocrine carcinoma grades varied, with G1 being seen in 15% of patients, G2 in 55%, and G3 in 30%. In contrast, 100% of NA-TNC cases were G3. The majority of apocrine carcinomas presented at low T stage (T1: 70%; T2: 20%; T3: 10%; T4: 0%), whereas NA-TNC cases more often presented at T2 or higher (T1: 46.2%; T2: 30.8%; T3: 11.5%; T4: 11.5%). Thirty percent of apocrine carcinomas and 30.8% of NA-TNCs had nodal metastases at presentation. Apocrine carcinomas had a favorable clinical prognosis, with 80% of patients showing no evidence of disease-related morbidity or mortality (mean follow-up: 45.2 mo). Pure apocrine carcinomas represent a clinicopathologically distinct subgroup of triple-negative breast cancer characterized by AR positivity. When compared with NA-TNC, apocrine carcinomas more often present in older women with lower grade and T stage, a group in which a more conservative treatment regimen is often desired.