Evaluation of RIP1K and RIP3K expressions in the malignant and benign breast tumors

Receptor-interacting protein kinase 1 (RIP1K) and RIP3K belong to RIPK family, which regulate cell survival and cell death. In the present investigation, the expression levels of RIP1K and RIP3K were evaluated in the 30 malignant, 15 benign, and 20 normal breast tissues, and their correlation with clinicopathological characteristics was also studied. The expression levels of RIP1K and RIP3K were determined, by western blot analysis. The relative RIP1K expression was significantly higher in the malignant and benign tumors when compared to those of normal tissues (P < 0.0001 and P < 0.001, respectively). However, the expression level of RIP3K was significantly lower in the malignant tumors than those of normal and benign values (P < 0.001 and P < 0.01, respectively). Positive significant correlation was found for RIP1K expression with tumor size (P < 0.001), grades (P < 0.0001), and c-erbB2 (P < 0.001), but negative significant correlation was detected with patient’s age (P < 0.001), estrogen receptor (ER) (P < 0.001), progesterone receptor (PR) (P < 0.01), and P53 (P<0.01) status. RIP3K expression was significantly lower in the pre-menopauses (P < 0.01), grade III (P < 0.05), ER-negative (P < 0.05), and c-erbB2-negative malignant tumors, but no correlation was detected with tumor size, PR, and P53 status. No significant correlation was observed for RIP1K and RIP3K expressions with Ki67 and Her2. Based on the present results, it is concluded that reduction of RIP3K expression in the malignant breast tumor might be an important evidence to support the antitumor activity of this enzyme in vivo. However, RIP1K expression was shown to be higher in the malignant breast tumors than those of normal and benign breast tissues, which probably designates as a poor prognostic factor.