2 Nearly all SCLC arise in smokers and have RB1 & TP53 mutations.
Over the years, we encountered exceptional patients breaking all the rules: pathology of SCLC, but with intact RB1 & TP53, and generally never/light smokers. These are rare (3% of SCLC), but solving them was an opportunity to uncover unique biology and to inform diagnosis and treatment for when these patients are encountered in practice.