CHEK2 and Li-Fraumeni syndrome: Based on their prevalence in previous studies [27–36] and our clinical experience in dermatology, we focus on Li-Fraumeni syndrome (LFS), Lynch syndrome (LS), hereditary breast and ovarian cancer (HBOC) syndrome, ATM-associated hereditary cancer syndrome, CHEK2-associated hereditary cancer syndrome, cancer predisposition associated with BRIP1 mutations, and hereditary leiomyomatosis and renal cell carcinoma (HLRCC) in this narrative review.