Subsequently, an indirect immunoperoxidase technique was applied, using monoclonal antibodies for Telomerase (hTERT) (clone 2C4, concentrated with 1:500 used dilution; Abcam catalogue No ab5181), Retinoblastoma (Rb) (clone 1F8, prediluted; Thermo scientific, catalogue No #MS-107-R7), TP53 (monoclonal mouse anti-human antibody DO-7; Dako, Carpinteria, CA; dilution 1:4000), CDKN1A p21 (monoclonal mouse anti-human, SX118, Dako; dilution 1:2000, FGFR3 (monoclonal mouse anti-human, clone B-9; Santa Cruz Biotechnology). This evidence concerns the gene CDKN1A and retinoblastoma.