The number of leukocytes infiltrating the tumours, determined by staining with the pan leukocyte marker CD45 (anti-CD45-Alexa 633), or the number of B cells detected with CD19 antibodies (anti-CD19 Alexa-549), was not different in tumours from mice treated with extracts of Uncaria tomentosa or vehicle suggesting a specific infiltration of immune cells into the tumour. This evidence concerns the gene CD19 and neoplasm.