PIK3CA and thymic carcinoma: Moreover, using a TumorMap approach, it was possible to expand the four-tiered clustering of TETs (Figure 2): type A and AB thymoma clusters were defined by GTF2I mutations, and the overexpression of a large miRNA cluster on chromosome 19q13.42 activating the PI3K/mTOR pathway, while type C cluster (i.e., thymic carcinomas) was defined by chromosome 16q loss.