Hemolymphoreticular Neoplasias from the Ramazzini Institute Long-term Mice and Rat Studies on Aspartame

Abstract

Background: Haemolymphoreticular neoplasias (HLRNs) from the Ramazzini Institute (RI) carcinogenicity studies on Aspartame (APM) in rats and mice were heterogeneously grouped over the years and different statistical methods were applied. Objective: We report all the detailed HLRN diagnoses of all the RI rats and mice studies on APM and the related statistics. Methods: Histological subtypes and lineage (myeloid or lymphoid) are reported in males (MM) and females (FF) in line with the International Harmonization of Nomenclature and Diagnostic Criteria for Lesions (INHAND) for rodents and the World Health Organization (WHO) Classification of Tumours of Haematopoietic and Lymphoid Tissues. Statistical analyses included Fisher’s Exact test and Cochran-Armitage trend test. Findings: Results from the post-natal bioassay on Sprague-Dawley (SD) rats (BT6008) showed statistically significant increases in lymphomas (all types) (MM, FF), leukemias (all types) (FF), immunoblastic lymphomas (MM, FF), total lymphoid tumours (MM, FF), monocytic leukemia (FF), myeloid leukemia (FF), histiocytic sarcoma (FF), and total myeloid tumours (FF). Results from the prenatal experiment on SD rats (BT6009), showed statistically significant increases in lymphomas (all types) (FF), leukemias (all types) (FF), total lymphoid tumours (FF), myeloid leukemia (FF), and total myeloid tumours (FF). Finally, results from the prenatal bioassay on Swiss mice (BT6010) showed statistically significant increases in leukemias (all types) (MM, FF), lymphoblastic leukemia (MM, FF), monocytic leukemia (MM) and total myeloid tumours (MM). Conclusions: Our analyses, performed in line with international recommended guidelines for statistics and pathology, confirm and reinforce our previous findings of statistically significant increases of HLRNs in rodents exposed to APM.