CDKN2A and melanoma: Antisense non-coding RNA in the INK4 locus (ANRIL) was discovered after sequence-tagged site reverse transcriptase polymerase chain reaction (RT-PCR) based gene dose mapping of the entire INK4/ARF locus in a family with melanoma and neural system tumors.[52, 53] ANRIL is transcribed as a lncRNA in the antisense orientation relative to the P15/CDKN2B/INK4B-P16/CDKN2A/INK4A-P14/ARF cluster.