CD4 and lymphoma: BM flow cytometry gating on the lymphoma cells confirmed the positive expression of CD2, CD3, CD7, CD8, CD56, T‐cell receptor (TCR) alpha‐beta chains, perforin, granzyme B, and negative for CD34, CD4, CD5, and TCR gamma‐delta chains (Figure 2), consistent with natural killer (NK)/T lymphoma involvement.