GSTM1 and colorectal neoplasm: Evaluation of the ordinal property of a biomarker such as f-Hb that is measured by FIT and is widely used for population-based CRC screening is difficult because, in addition to the skewed property of such an ordinal data, the dynamic nature of f-Hb during the repeated FIT test, the multistage outcome of colorectal neoplasm, and the relationships of the upper and lower limits to the status of colorectal neoplasm render the elucidation of the dynamics of f-Hb very intractable.