Determination of programmed death ligand 1 (PD-L1) expression defines eligibility for treatment with pembrolizumab in patients with advanced NSCLC. This study was designed to better define which value across core biopsy specimens from the same case more closely reflects the PD-L1 expression status on whole sections and how many core biopsy specimens are needed for confident classification of tumors in terms of PD-L1 expression. We built tissue microarrays as surrogates of biopsies collecting five cores per case from 268 cases and compared PD-L1 staining results obtained by using the validated clone SP263 with the results obtained by using whole tumor sections. We found an overall positivity in 39% of cases at a cutoff of 1% and in 10% of cases at a cutoff of 50%. The maximum value across cores was associated with high concordance between cores and whole sections and the lowest number of false-negative cases overall. To reach high concordance with whole sections, four and three cores are necessary at cutoffs of 1% and 50%, respectively. Importantly, with 20% as the cutoff for core biopsy specimens, fewer than three cores showed high sensitivity and specificity in identifying cases with 50% or more of tumor cells positive for PD-L1 on whole sections. Specifically, for PD-L1 expression values of 20% to 49% on cores, the probabilities of a tumor specimen expressing PD-L1 in at least 50% of cells on a whole section were 46% and 24% with one and two biopsy specimens, respectively. An accurate definition of the criteria to determine the PD-L1 status of a given tumor may greatly help in selecting those patients who could benefit from anti-programmed cell death 1/PD-L1 treatment.

Neuroendocrine carcinoma of the breast is considered a rare entity, and for this reason there are no data from prospective clinical trials on its optimal management. Early stage tumors are usually treated with the same strategy used for the other types of invasive breast cancer. Anthracycline- and taxane-based regimens represent the most frequently administered chemotherapy in neoadjuvant and adjuvant setting, as well as for metastatic disease, although combinations of platinum compounds and etoposide have been widely used, in particular for small-cell histology and tumors with a high proliferation index. For metastatic disease, a multimodality therapeutic strategy can be considered on an individual basis, with chemotherapy, endocrine therapy, peptide receptor radionuclide therapy, radiation therapy, surgery, or a combination of the above. In the near future, a better knowledge of the biology of these tumors will hopefully provide new therapeutic targets for personalized treatment. In this review, we discuss the current evidence and the future perspectives on diagnosis and treatment of neuroendocrine carcinoma of the breast.

Purpose: No evidence exists as to whether type 2 diabetes mellitus (T2DM) impairs clinical outcome from immune checkpoint inhibitors (ICI) in patients with solid tumors. Experimental Design: In a large cohort of ICI recipients treated at 21 institutions from June 2014 to June 2020, we studied whether patients on glucose-lowering medications (GLM) for T2DM had shorter overall survival (OS) and progression-free survival (PFS). We used targeted transcriptomics in a subset of patients to explore differences in the tumor microenvironment (TME) of patients with or without diabetes. Results: A total of 1,395 patients were included. Primary tumors included non–small cell lung cancer (NSCLC; 54.7%), melanoma (24.7%), renal cell (15.0%), and other carcinomas (5.6%). After multivariable analysis, patients on GLM (n = 226, 16.2%) displayed an increased risk of death [HR, 1.29; 95% confidence interval (CI),1.07–1.56] and disease progression/death (HR, 1.21; 95% CI, 1.03–1.43) independent of number of GLM received. We matched 92 metformin-exposed patients with 363 controls and 78 patients on other oral GLM or insulin with 299 control patients. Exposure to metformin, but not other GLM, was associated with an increased risk of death (HR, 1.53; 95% CI, 1.16–2.03) and disease progression/death (HR, 1.34; 95% CI, 1.04–1.72). Patients with T2DM with higher pretreatment glycemia had higher neutrophil-to-lymphocyte ratio (P = 0.04), while exploratory tumoral transcriptomic profiling in a subset of patients (n = 22) revealed differential regulation of innate and adaptive immune pathways in patients with T2DM. Conclusions: In this study, patients on GLM experienced worse outcomes from immunotherapy, independent of baseline features. Prospective studies are warranted to clarify the relative impact of metformin over a preexisting diagnosis of T2DM in influencing poorer outcomes in this population.

Contribution of KRAS mutations and c.2369C > T (p.T790M) EGFR to acquired resistance to EGFR-TKIs in EGFR mutant NSCLC: a study on circulating tumor DNA Contribution of KRAS mutations and c.2369C > T (p.T790M) EGFR to acquired resistance to EGFR-TKIs in EGFR mutant NSCLC: a study on circulating tumor DNA