In addition, once used in combination with tumor-associated aberrant immunophenotypes, the TRBC1 expression profile (negative vs. positive) of SmCD3+ cells shows a high sensitivity and specificity for detection of monoclonal Tαβ-cells in patients suspicious of T-CLPD, at similar levels to those reached with the kappa/lambda ratio in the diagnostic work-up of B-CLPD [43,44,48]. The gene discussed is TRBC1; the disease is neoplasm.