PIK3CA and cancer: However, upon analysing the dependency profiles on cancer genes that are commonly mutated in HNSCC and those with driver mutations among our 21 OSCC cell lines, we show that with the exception of some genes with driver mutations leading to oncogene addiction (PIK3CA, HRAS and NFE2L2), most other driver mutations did not confer preferential gene dependency and their value as a drug target remains unclear.