GSTM1 and colorectal carcinoma: Several studies using data from population-based CRC screening with FIT demonstrated a gradient relationship between f-Hb concentrations and the incidence of CRC, colorectal neoplasms, and CRC mortality.13,14,15,16,17 Such empirical findings underscore the potential of fine-tuning the use of quantitative f-Hb measurements as a means to devise individualized interscreening intervals for FIT-based CRC screening regimens.