Fig. 7. Tumor suppressor protein levels in early- and late-passaged chondrosarcoma cells. Side-by-side comparisons of early (E) and late (L) cultures of the CS lines are shown. CS-2 cells were analyzed at 2 and 106 PDs; CS-3 cells at 2 and 59 PDs; CS-4 cells at 2 and 58 PDs; and CS-8 cells at 2 and 43 PDs. Ten µg of total protein were loaded in all lanes, except for the p16ink4a late-passaged lanes, which were loaded with 20 µg of total protein. The hypophosphorylated (o) and hyperphosphorylated (p) forms of pRb are indicated.