MKI67 and neoplasm: We compared the MPM#2 xenografts (P16, NF2 and BAP1 altered) that had a very low percentage of tumour cells staining positive for Ki-67, to MPM#26 xenografts (P16 and NF2 altered) which stained moderately for Ki-67, and MSTO-211H xenografts (P16 altered) that had an extremely high frequency of Ki-67 staining.