CHEK1 and rectal cancer: Several studies identified SNPs in genes functioning in DNA damage and repair in other types of cancers such as; rs3218556 in XRCC2 and rs13181 in XPD were associated with mucositis in non-small-cell lung cancer (NSCLC) [78], rs61915066 in ATM, rs11220184 in CHEK1, rs302877 and rs405684 in RAD51C, and rs60152947, rs10404465, rs1799786 in ERCC2 which were associated with early adverse skin reaction (i.e., dermatitis) post-RT in breast cancer [79] and rs1233255 in PMS1 gene was associated with RT-acute dermatitis in rectal cancer [80].