CDKN2A and head and neck squamous cell carcinoma: It was noted in an Indian investigation that additional risk factors had an impact on p16INK4a expression in this location, since almost 60% of HNSCC specimens testing HPV DNA/mRNA-double-positive were p16INK4a-negative and approximately 18% of HPV mRNA-negative HNSCCs were p16INK4a-positive [149].