PTPN3 and large cell neuroendocrine carcinoma: Previous research has indicated that PTPN3 plays a pivotal role as an immune checkpoint in activated lymphocytes, and inhibition of PTPN3 in lymphocytes expands the proportion of tumor-infiltrating lymphocytes and activated lymphocyte cytotoxicity, thus exerting the anti-cancer effects on SCLC and LCNEC progression [21, 31].