Schematic representation of the RASSF1 locus on chromosome 3p21.3 and its transcription map. White boxes represent the exons and the bold line represents the introns. RASSF1A, RASSF1B and RASSF1C variants are generated by differential promoter usage (arrows). RASSF1D, E, F, G are variants derived from alternative splicings of RASSF1A. Two CpG islands (black bands below the sequence) are associated to RASSF1 promoter region: CpG island A (737 bp, 85 CpGs) extending in the promoter region of RASSF1A, D, E, F and G; CpG island C (1365 bp, 139 CpGs) in the regulatory region of RASSF1B and C.