RB1 and small cell lung carcinoma: In a gene expression profiling study using SCLC cell lines, McColl et al. showed that the rare RB1 WT subtype expressed YAPI (currently classified as SCLC-Y) and was chemo-resistant, while INSM1 (insulinoma-associated protein 1) expressing subtype (SCLC-A and SCLC-N) was chemosensitive [14].