The presence of high blood involvement (B score = 2, according to the TNMB classification) is a diagnostic criterion for SS and is defined by different parameters, such as in addition to the demonstration of clonally related neoplastic T cells in the skin and peripheral blood, either an absolute Sézary cell (SC) count of >1000/μL, or an expanded CD4+ T-cell population resulting in a CD4/CD8 ratio ≥ 10, CD4+/CD7− cells ≥ 30%, or CD4+/CD26− cells ≥ 40% are required [3]. The gene discussed is CD4; the disease is synovial sarcoma.