H2AX and small cell lung carcinoma: Although significant correlation between SRSF1 and Top1 gene expression is not observed in our data, our experiment clearly demonstrates that SRSF1 loss induces phosphorylated H2AX signal in SCLC cell lines, which suggests that SRSF1 may help maintain the genomic integrity of SCLC to safeguard against DNA-damage and cell death.