Clinical Significance of Soluble Major Histocompatibility Complex Class I Chain-related A in Renal Cell Carcinoma Patients

Objective: Major histocompatibility complex class I chain-related A (MICA) is a stress-inducible glycoproteinthat can be shed as a soluble protein. This study was conducted to determine the expression of MICA in renalcell carcinoma (RCC) and examine the clinical relevance of soluble MICA (sMICA) in this disease.
Methods:Immunohistochemistry and real-time PCR analyses were performed to assess the expression of MICA in 48pairs of RCC and adjacent normal renal tissues. Serum levels of sMICA were measured in 48 RCC patients,12 patients with benign renal tumors, and 20 healthy individuals. The correlations between sMICA levels andclinicopathological parameters were analyzed and the diagnostic performance of sMICA in RCC was evaluated.
Results: RCCs exhibited elevated expression of MICA compared to adjacent normal tissues. Serum concentrationsof sMICA were significantly greater in RCC patients (348.5 ± 32.5 pg/ml) than those with benign disease (289.3± 30.4 pg/ml) and healthy controls (168.4 ± 43.2 pg/ml) and significantly correlated with advanced tumor stage,lymph node metastasis, distant metastasis, vascular invasion, and higher histological grade. Using a cut-off pointof 250 pg/ml, sMICA demonstrated a specificity and sensitivity of 63.2% and 75.6%, respectively, in distinguishingbetween RCC and benign renal tumors.
Conclusion: MICA expression is upregulated in RCC and increasedserum sMICA levels predict aggressive tumor behavior. However, the applicability of sMICA alone is limited indistinguishing RCC from benign renal tumors.