The top fifteen genes in cancer tissues that were found in this study to be significantly hypomethylated in their promoters in comparison to control healthy tissues (TRBC2, DGAT2, ALG1L, PDE4D, TRDC, DNAJC6, IGKV3-20, TMEM150B, LAIR2, UBQLN3, ANKFN1, MS4A1, CCT8L2, SPOCK1, and IGHV4-39) are mainly involved in the immune response, i.e., IGHV4-39 (antigen recognition gene), IGKV3-20 (immunoglobulin receptor binding gene), LAIR2 (innate immune response gene), MS4A1 (differentiation of B cells gene), TRBC2 and TRDC (both T cell receptor genes). The gene discussed is IGKV3-20; the disease is cancer.