B7-H4 Expression is Associated with Cancer Progression and Predicts Patient Survival in Human Thyroid Cancer

Objective: This study aimed to investigate the expression of B7-H4 in human thyroid cancer and determineany association with patient clinicopathological parameters and survival.
Methods: B7-H4 expression in 64clinical thyroid cancer specimens was assessed with immunohistochemistry. Moreover, B7-H4 mRNA expressionin 10 fresh resected specimens were evaluated by the reverse transcription-polymerase chain reaction (RT-PCR).Immunohistochemical staining of CD3 was performed to assess the number of tumor infiltrating T lymphocytes(TILs) in thyroid cancers.
Results: Positive B7-H4 immunohistochemical staining was observed in 61 out of 64(95.3%) specimens of thyroid cancer tissues. Significantly more B7-H4 mRNA copies were found in thyroidcancer tissue than that adjacent normal tissue. Moreover, B7-H4 expression in human thyroid cancer tissues wassignificantly correlated with patient TNM stages and extrathyroidal extension (P<0.05), being inversely correlatedwith the number of TILs (P<0.05). The overall survival rate of the patients with higher B7-H4 expression wassignificantly worse than that of the patients with lower B7-H4 expression.
Conclusions: This present studysuggests that high B7-H4 expression is associated with cancer progression, reduced tumor immunosurveillanceand worse patient outcomes in human thyroid cancer.