Clinical significance of mrp gene in primary hepatocellular carcinoma

To study the relations among the expression of the multidrug resistance associated-protein (mrp) gene and clinicopathologic features, the influence of alpha-fetoprotein (AFP), and prognosis of patients who received adjuvant chemotherapy after resection of primary hepatocellular carcinoma (HCC).

The expression of the mrp gene encoding MRP and mRNAmrp was determined in tissues from 54 untreated patients with HCC, adjacent tissues from 24 patients with HCC and archival paraffin-embedded tissues from 12 patients with posthepatic cirrhosis. The relationship between the mrp gene expression and the change level of AFP was analyzed in the 24 postoperative HCC patients whose AFP level was measured after 2 weeks. All of the HCC patients were followed up.

The percentage of positive expressions of MRP and mRNAmrp in the three kinds of tissues was 57.40%, 25.00%, 16.67%, and 72.22%, 37.50%, 33.33% respectively. Significant difference was noted in the untreated HCC tissue, compared to the other two tissues (P<0.05). No difference existed between the mrp gene expression and such clinicopathologic findings, as age, sex, and tumor size (P> 0.05), but the expression was related to the degree of differentiation of HCC (P<0.05). The effective rate of AFP in the mrp gene positive expression group or postoperative chemotherapeutic patients was lower than that in the negative group (P<0.05). Although no difference was seen in the 1-, 3-, 5-year survival rates of HCC patients (P>0.05), the mean survival time of postoperative HCC patients or the negative mrp gene expression group was longer than that of the positive group (P<0.05).

Multidrug resistance (MDR) of HCC is related to mrp gene expression and initiates the intrinsic MDR. Detection of mrp gene expression is of great significance in accessing chemotherapeutic resistance of HCC, which provides evidence for reversing MDR in HCC. The mrp gene may be a useful marker in detecting prognosis of HCC patients because its expression is correlated with tumor differention and mean survival time of the patients.