EGFR and colorectal carcinoma: Research showed that the Kirsten rat sarcoma viral oncogene homolog (KRAS) gene, an important member of the EGFR signalling cascade, can acquire activating mutations in exon 2 codons 12 and 13 in approximately 35.0–45.0% of the CRC cases, rendering EGFR inhibitors ineffective [4, 5].