Despite this cyclic pattern of expression, coupled with very low levels of FasL mRNA for some cell lines (e.g. HCT116 colon carcinoma cells were positive for FasL mRNA at only 3 of the 13 time points examined (3, 27 and 60 hours)), all cells were observed to constitutively express FasL protein as assessed by Western blotting (Figure 1B). This evidence concerns the gene FASLG and colon carcinoma.