Heatmap illustrating selected clinicopathologic features, histochemical, and mutational status, including single‐nucleotide variants and copy‐number alterations, of MECs. Each column represents a patient, according to their ID, each row represents a clinicopathologic and genetic parameter, color‐coded according to the legend on the bottom right. The number of genomic alterations detected in each case is represented in the bar chart at the bottom of the figure, while the frequency of recurrent actionable/pathogenic mutations is reported on the right as a percentage. AREG, amphiregulin; CK, cytokeratin; CNV, copy‐number variations; CPS, combined positive score; ER, estrogen receptor; MMR, mismatch repair; PD‐L1, programmed death‐ligand 1; SNV, single‐nucleotide variants; TILs, tumor‐infiltrating lymphocytes; WT, wild‐type.