Kaplan − Meier estimate and cumulative incidence curve of the disease-free survival of colorectal cancer patients as a function of ERβ1 and ERβ5 isoform expression levels (primer pair 2: transcript variants a and g). The cutoff for relative gene expression of −4.5 (log2) was determined using the log-rank test (maximally selected rank statistics in R) [24] (PNG 86 kb)