PIK3CA and neoplasm: The SCLC samples featured significantly lower frequencies of GAs in PIK3CA, MYC, and ARID1A. In contrast, the HGNECC samples featured significantly lower frequencies of GAs in TP53 and RB1. High-risk HPV was identified in much less than 1% of SCLC tumor samples compared with 85.6% of HGNECC tumor samples.