Neuroendocrine tumors of an unknown primary site are difficult to identify but their incidence is higher than previously reported, and the prognosis remains unfavorable.
While the mammalian target of rapamycin (mTOR) signaling pathway is a promising target for well-differentiated endocrine carcinoma therapy with the mTOR inhibitor everolimus (RAD001), poorly differentiated endocrine carcinomas (PDECs) are usually excluded from clinical trials due to their aggressiveness. So far, mTOR activity in PDECs has only been tested in cell lines. This study reviewed 36 mono-institutional PDECs to determine mTOR expression. Slides of normal kidney as positive control were used to optimize mTOR staining. To ensure antibody specificity, consecutive sections were incubated in the absence of primary antibody. Immunoreactivity was evaluated on a semi-quantitative scale scoring the extent and intensity of staining. The product of these two scores was used to obtain a total immunostaining score. The main primary site of disease was the pancreas, and 83% of patients had stage IV disease. In 80% of samples, mTOR expression was maintained at similar levels, with no relationship to tumor origin or proliferation rate determined by MIB-1. This study seems to demonstrate that mTOR is expressed in human PDECs regardless of tumor site. Its role in relation to the activity of everolimus in this subset of patients needs to be confirmed.
Innovative therapeutic agents have significantly improved outcome with an acceptable safety profile in a substantial proportion of non-small cell lung cancer (NSCLC) patients, who depend on oncogenic molecular alterations for their malignant phenotype. Despite the survival improvement achieved with first-line chemotherapy, about 30% of patients do not obtain a tumor response. Moreover, those patients, initially sensitive to treatment, acquire resistance and develop tumor progression after a median of about 5 months. Approximately 60% of the patients progressing from first-line chemotherapy receive further systemic treatment in the second-line setting. Moreover, new options have emerged in the second-line armamentarium for the treatment of patients with NSCLC, including immune checkpoint inhibitors and antiangiogenic agents. The current review provides an overview on the clinical studies that gained the approval of chemotherapy agents (docetaxel and pemetrexed) and epidermal growth factor receptor gene–tyrosine kinase inhibitors as second-line treatment options for NSCLC patients, not carrying molecular alterations.
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