Let‐7b has tumour suppressor activity and regulates cell cycle.10 Suppression of Let‐7 family members has been reported in many cancers.21, 22, 23 KRAS, a potent proto‐oncogene,24, 25 is mutated in a wide variety of human malignancies26, 27, 28, 29, 30, 31 and up‐regulated in endometriosis. This evidence concerns the gene KRAS and cancer.