The Expression Of PD-L1/PD-L2 And Clinical Significance In Chondrosarcoma Patients

Purpose: Chondrosarcoma(CHS)is a malignancy affecting cartilage and is chemoand radio-resistant.Novel immune checkpoint may be play a great role in treatment,and PD-L1/PD-L2,however at present in CHS clinical studies and analisis data insufficient.Methods: 59 cases of CHS were collected between 1997 to 2017,and stained by immunohistochemistry(IHC)for PD-L1,PD-L2,Ki-67,and p53.Clinicopathological parameters were collected and analyzed statistically for associations and prognosis analysis.PD-L1,PD-L2 positivity was designated using 1% and 5% cutoffs,respectively.Results: 40 cases(67.8%)were assessed as PD-L1 positive and 25 caese(42.4%)were PD-L2 positive using.PD-L1 positivity was significantly associated with younger age(P=0.001),larger tumor(P=0.025),advanced tumor grade(P<0.001),and recurrence(P<0.001),and survival time for patients with high PD-L1 expression was statistically significant(P=0.0008).PD-L1 positivity was not associated with gender,location,serum level of lactate dehydrogenase(LDH)or alkaline phosphatase(ALP).PD-L2 positivity was significantly associated with younger age(P=0.015)and recurrence(P=0.014),was not associated with gender,tumor size,location,serum LDH or ALP level,or tumor grade.PD-L1 expression was significantly correlated with Ki-67(P<0.001)and p53(P=0.02)expressions.PD-L2 expression was not correlated with either Ki-67 or p53.When grouped as combined expression(both negative and either positive),PD-L1/PD-L2 expression was correlated with expression of Ki-67(P<0.001)but not with p53.Conclusion: PD-L1/PD-L2 expression is positive in CHS and is associated with advanced clinical phonotype and with poor prognosis.PD-L1/PD-L2 expression is also significantly associated with Ki-67 expression.Our results support the application of immune check point inhibition may blockade in CHS.