NFIB and colon carcinoma: Because the specific mechanisms by which the NFIB genotype is related to reduced CLZ levels remain unknown, the aim of the present study was to explore the impact of NFIB genotype on the formation of 30 CLZ metabolites in a large patient sample with known tobacco smoking habits, as well as to assess NFIB’s effect on the expression of genes encoding for CLZ transporters in colon carcinoma Caco-2/TC7 cells.