KRAS mutations account for 7% of prostate cancer (PCa) cases, leading to the activation of downstream effector proteins.128 Mutant KRAS plays a transformative role in PCa tumorigenesis by promoting cancer stemness and metastasis to bone, with KRAS rearrangements shown to promote PCa metastatic progression.153–156 In melanoma, while mutations in KRAS are even rarer, accounting for only 1.7% of cases, inhibiting its downstream effector BRAF is one example of a success story of targeting downstream effectors of KRAS for cancer therapy. The gene discussed is KRAS; the disease is posterior cortical atrophy.