CTSL2 or cathepsin L2 gene, a pro-apoptotic target of E2F1 and a modulator of apoptosis [42] previously reported to be upregulated in several human tumors including breast and colon carcinoma [43], is downregulated in the HCC827-derived cell lines RA1, RB1, RB1.1 and RB2 as well in the HCC4006-derived RC2.2 cell line (Figure 8b, 8c). The gene discussed is E2F1; the disease is colon carcinoma.