XPC and xeroderma pigmentosum: Within the NIH, UK, and published case reports (21–31), there were 22 XP patients treated with ICI: 14 XP-C patients (XPC gene), one XP-D patient (ERCC2 gene), two XP-E patients (DDB2 gene), three XP variant patients (POLH gene), and two patients with unreported XP mutations (Table 1; Supplementary Tables S1–S3).