LAPTM4B and neoplasm: In view of the latter and given the extensive evidence of LAPTM4B's involvement in neoplasia, as well as its demonstrated relation to histologic grade and tumor recurrence in some cancers, it is likely that this 19-bp sequence plays an important role in genetic transcriptional regulation or that the extra 53 amino acids at the N terminus produced by LAPTM4B* 2 may influence physiological activity and function in tumor cells.