RET and cancer: After splitting up the tumors according to genotype cluster (i.e. cluster 1: SDHx- and VHL-related PCC/PGL; cluster 2: RET-, NF1-, and TMEM127-related tumors), malignant tumors (n = 24) clustered more often in genotype cluster 1 (P<0.0001), compared to benign tumors (n = 33).