PDPK1 and cancer: Irrespective of possible differences in PDPK1 function in early vs late or primary vs metastatic tumors as a possible explanation of the observed PDPK1 expression pattern on our cancer tissue microarrays, the association of the heterogeneous PDPK1 expression pattern with important clinicopathological outcomes appears to be in line with the intratumoral heterogeneity of this regulator found to be overexpressed and activated in the LRCC vs NLRCC subpopulations where it is essential for chemoresistance.