The morphology of xenograft tumors strongly resembled that of the corresponding patient tumors; however, some differences were observed as follows: the xenografts tended to show more solid architecture with less surrounding stroma than did the primary human tumors, and most xenografts had a higher grade with little to no tubule formation, more prominent nuclear pleomorphism and a higher rate of proliferation by both mitotic count and Ki-67 staining regardless of the grade or histology of the original human tumor. Here, MKI67 is linked to neoplasm.