BCL2 and follicular lymphoma: Small abnormal B-cell populations may represent monoclonal B-cell lymphocytosis (see above) [17,18,43] or in situ follicular neoplasia (often now called in situ follicular B-cell neoplasm), a precursor lesion of follicular lymphoma showing colonization of morphologically normal geminal centers that harbor the t(14;18) of follicular lymphoma and aberrantly co-express CD10 and BCL-2 [44,45].