PTPRC and cancer: The total amount of CK (+) cells in a CD45-negative subset gradually increased as the malignancy progressed from CIN1 to carcinoma in situ, and in invasive carcinoma of stage IA, it became significantly higher than in controls (p < 0.05, U-test), while the amount of EpCAM (+) cells was elevated in CIN1 samples (p < 0.05), showing no significant changes at higher CIN grade and cancer (Figure 15).