Although the patient did not undergo molecular testing for mutations in genes such as PTCH1 or AS3MT, which have been associated with increased susceptibility to BCC and altered arsenic metabolism, and no biomarker measurements (e.g., hair, nails, urine, tissue) were performed to confirm residual body burden, the minimal lifetime UV exposure combined with the multifocal distributions of lesions remain strongly aligned with epidemiological and clinical descriptions of arsenic-induced BCC [2,7,14]. Here, PTCH1 is linked to skin basal cell carcinoma.