CD7 and leukemia: There are four subtypes of T-ALL according to the European Group for the Immunological Classification of Leukemia (EGIL): pro-T EGIL T-I (iCD3+, CD7+), pre-T EGIL T-II (iCD3+, CD7+ and CD5/CD2+), cortical T EGIL T-III (iCD3+, Cd1a+, sCD3+/−), and mature-T EGIL T-IV (iCD3+, sCD3+, CD1a−) [25].