PTPRG and neoplasm: During the identification of Ptprg as a candidate tumor-suppressor gene, the analysis by Wary et al. (1993) of malignancy-inducing homozygous deletions in murine L-cell sarcoma cell lines (Sanford et al., 1948) showed that the Ptprg gene in these cells is missing a 200-kb fragment that includes exons 3–5 and flanking intronic sequence.