ESR2 and neoplasm: On the basis of the correlations among all the 15 genes obtained using a non-parametric approach along with the individual gene performance, six genes (APC, VGF, MGMT, hMLH1, ER-β and FKBP4) were shown to be independent of each other and each of them shows the strongest predictive potential representing the corresponding cluster, and thus, were selected to be included in a multivariable logistic regression model that modelled the probability of tumour.