S1PR2 and mantle cell lymphoma: SLO lymphomas [comprising 10 follicular lymphoma (FL), 8 diffuse large B-cell lymphoma (DLBCL), 4 mantle-cell lymphoma (MCL) and 5 marginal-zone lymphoma (MZL)] were characterised by pronounced over-expression of S1PR2, suggesting that the malignant cells in these lymphomas are actively retained at the site of clonal expansion.