In one MEN2A patient, we were able to analyze both PHEO and MTC tumor tissues simultaneously for the three genes: for PHEO, LAT1 expression was 41 times higher than in normal tissues, while LAT2 and GLUT1 genes were expressed on much the same levels as in normal tissue; for MTC, on the other hand, LAT1 expression was 6.5 times higher while that of LAT2 was 3.1 times and that of GLUT1 was 5 times higher than in normal thyroids. This evidence concerns the gene SLC7A5 and multiple endocrine neoplasia type 2A.