Skp2 and salivary cancer

Salivary malignancies are rare, heterogeneous, unpredictable in clinical behavior and seldom studied. Skp2 expression was examined in salivary malignancies (n = 75) for a prolonged period (20 years). In 40/75 (53%) cases Skp2 expression rate (staining level) was < or =4% while in the remainder (47%) it was >4%. Correlation between enhanced Skp2 and enhanced p53 staining levels was significant (p = 0.042), as were correlation rates between enhanced Skp2 and reduced p27 staining levels (p = 0.01) and enhanced Skp2 and enhanced TUNEL staining levels (p = 0.008). Survival probability rates dropped when Skp2 expression increased. Median patient survival for reduced-stained-tumor patients (< or =4%) was 143 months and significantly lower, 49 months (p = 0.016), for enhanced-stained-tumor patients (>4%). Survival probability at 5 years was 82% for the former group (< or =4%) and 47% for the latter (>4%). At 20 years, survival dropped to 35% and 18% respectively (p = 0.016). More extensive and aggressive therapy did not reduce mortality in patients with enhanced Skp2-expressing tumors. Significant correlations between poor survival and significantly altered expression rates of Skp2, p27, p53, TUNEL and heparanase in salivary malignancies, suggest a biological role in salivary cancer pathogenesis for these 5 markers. The findings may be used for prognostic and follow-up purposes.