Diagnosis of adenocarcinoma is often based on identification of molecular markers of mutations, in particular EGFR, ERCC (DNA excision repair protein), RRM 1 (ribonucleoside-diphosphate reductase), KRAS (KRAS proto-oncogene), TS (thymidylate synthetase), and EML4-Alk (anaplastic lymphoma kinase receptor tyrosine kinase) [78]. Here, KRAS is linked to adenocarcinoma.