The phosphoinositide 3-kinase (PI3K)/AKT1 pathway is acknowledged as a key component of cell survival. Activated by receptors or the small GTPase Ras, the various PI3K isoforms phosphorylate inositol lipids to form second messenger phosphoinositides. PI3K family members have long been accepted as oncogenes.

Pivotal studies indicate a role of excision repair cross-complementation 1 (ERCC1) gene and ribonucleotide reductase M1 (RRM1) gene in conferring a differential sensitivity to cytotoxic chemotherapy and epidermal growth factor receptor (EGFR) gene has been recently extensively investigated in non-small-cell lung cancer (NSCLC).

The test must be conducted on the tumour tissue. Tumour tissue removed from the body (following biopsy or surgery) is processed into a tissue block and stored at the hospital where the operation takes place. Once a decision is made to test for KRAS mutations, the patient's doctor will arrange to have a portion of that saved tissue block sent to a laboratory where KRAS testing is conducted. Results are then sent back to the treating physician. The testing process may take up to 2-3 weeks.