In epithelial/carcinoma cells, matriptase tends to be expressed with similar levels of HAI-1 based on the relatively narrow distribution of the log HAI-1/matriptase ratio of between 0.5 and −0.5 among the majority of these epithelial/carcinoma cells, indicating that the HAI-1:matriptase mRNA ratio varies between 3 and one third. Here, SPINT1 is linked to carcinoma.