S1PR1 and neoplasm: Previously, we found a greater proportion of T-cells having a Treg phenotype in FL compared to NLN partially due to FL tumor cell elaboration of CCL22 which is chemotactic for CCR4 expressing Treg-cells.[14] Present data suggest an additional novel mechanism, namely, the lack of expression of S1P1 in FL but not NLN Tregs, a type 1 G-protein coupled receptor that is a primary determinant for lymphocyte egress from the lymph node.