Differential retinoblastoma and p16INK4A protein expression in neuroendocrine tumors of the lung

摘要: BACKGROUND Neuroendocrine neoplasms of the lung represent a wide spectrum phenotypically and biologically distinct entities. Their histopathologic diagnosis, which carries therapeutic prognostic significance, may sometimes be difficult because their overlapping features. We previously demonstrated that large cell neuroendocrine carcinomas (LCNECs) small (SCLCs) failed to show positive nuclear staining RB protein (RB−), whereas typical atypical carcinoids (TCs ACs) showed immunostaining (RB+). METHODS In current study, series 58 surgically resected tumors, 33 tumors were initially diagnosed as SCLCs 25 TCs or ACs, studied for p16 expression by immunohistochemistry. They also reviewed pathologic diagnosis; reviewers blinded status. RESULTS Nineteen TCs, 5 7 LCNECs, 27 SCLCs. Three seven LCNECs RB+, other four RB−. In contrast, all 19 RB+ addition, two five ACs three Interestingly, 3 1 AC tested in any tumor cells (p16−), although some normal stromal (p16+) internal controls, indicating loss function these tumors. It is noteworthy one RB− was considered TC. With exception significantly more prevalent among heavy smokers with >20 pack-years compared nonsmokers light ≤20 (P < 0.01). CONCLUSIONS These findings suggest have abnormalities p16:RB pathway, do at least certain pathway TCs. Cancer 2000;88:550–56. © 2000 American Society.