High expression of Dll4 and CD44V6 is associated with clinicopathological characteristics and poor prognosis in osteosarcoma patients

Background: Osteosarcoma is a malignant tumor with a poor prognosis. Dll4 and CD44V6 are involved in the regulation of tumor development. This study aims to analyze the expression of Dll4 and CD44V6 in osteosarcoma and the correlation with clinicopathological characteristics and prognosis. Methods: Clinical data of 47 patients with osteosarcoma admitted to our hospital from April 2016 to May 2018 and confirmed by surgery or pathological examination were retrospectively analyzed. Osteochondroma and normal bone tissues from these cases were taken as controls. The protein levels of Dll4 and CD44V were detected by immunohistochemistry (IHC). The relationship between the expression of Dll4 and CD44V and the clinicopathological characteristics of patients with osteosarcoma was analyzed. An unconditional multi-factor logistic regression model was used to analyze the risk factors affecting the prognosis of patients with osteosarcoma. Results: The positive expression rates of Dll4 and CD44V6 in osteosarcoma were 85.11% (Dll4) and 91.49% (CD44V6), which were significantly higher than those in normal bone tissues of 18.52% (Dll4) and 7.41% (CD44V6), and in osteochondroma of 22.22% (Dll4) and 7.41% (CD44V6). The expression of CD44V6 and Dll4 were related to the Enneking stage and metastasis (P<0.05), and the expression of Dll4 was closely related to the degree of tumor differentiation (P<0.05). The 2-year survival rates of patients with Dll4 or CD44V6 positive expression were 25.00% and 21.88%, respectively, which were significantly lower than those with Dll4 or CD44V6 negative expression (85.71% and 93.33%) (P<0.05). The results of the unconditional multivariate logistic regression analysis showed that low tumor differentiation, high Enneking stage, metastasis, and positive expression of Dll4 and CD44V6 were risk factors affecting the mortality rate and prognosis of patients with osteosarcoma (P<0.05). Conclusions: The positive expression rate of Dll4 and CD44V6 in osteosarcoma is high, and the expression level is closely related to the degree of tumor differentiation, Enneking stage, and metastasis. Dll4 and CD44V6 are risk factors affecting the survival prognosis for patients. Therefore, in clinical settings, the prognosis for patients could be evaluated by detecting the expression of Dll4 and CD44V6.