These markers include FAT1 mutations, CD28 mutations in AITL, CDKN2A deletion in PTCL‐NOS, GATA‐3 expression, and TP63 structural abnormalities in ALK–ALCL (Table 5).24, 25, 26, 27, 28, 29, 30. The gene discussed is CDKN2A; the disease is anaplastic large cell lymphoma.