Nonetheless, some intronic polymorphisms are effective markers: For example, rs2237892 in intron 15 of KCNQ1 is associated with susceptibility to type 2 diabetes mellitus in Japanese individuals [81], and the CA simple sequence repeat in intron 1 (CA-SSR1) of the gene of epidermal growth factor receptor (EGFR) is associated with the clinical outcome in gefitinib-treated Japanese patients with non-small cell lung cancer [82]. Here, EGFR is linked to type 2 diabetes mellitus.