Expression of biogenesis of ribosomes BRX1 is associated with malignant progression and prognosis in colorectal cancer

BACKGROUND: Upregulated ribosome synthesis is associated with an increased risk of cancer onset. However, the role of biogenesis of ribosomes BRX1 (BRIX1), which is involved in the synthesis of ribosomal 60S subunits, in the progression and prognosis of colorectal cancer (CRC) is not clear. METHODS: Sixty CRC patients requiring surgical treatment were enrolled in the present prospective study. Patient characteristics were collected at admission. The CRC tissue samples and adjacent normal tissue samples from patients were collected for further quantitative reverse transcription-polymerase chain reaction and Western blot. All enrolled patients were followed up for 12 months, and overall patient survival during follow-up was recorded. RESULTS: The level of BRIX1 mRNA in CRC tissues was higher compared with that in adjacent normal tissues (1.0±0.5 vs. 5.5±1.7, P<0.01). Similarly, the level of the BRIX1 protein in CRC tissues was significantly higher than that in adjacent normal tissues (1.0±0.6 vs. 6.4±2.1, P<0.01). On further analysis, we found that the levels of BRIX1 mRNA and protein were positively correlated with tumor stage. Patients at stages III–IV had a higher expression of BRIX1 mRNA and protein than at stages I–II. The Kaplan-Meier survival curve indicated that patients with higher level of the BRIX1 protein had a lower overall survival rate. The Cox proportional hazards model was used to identify tumor stage III or IV, poor differentiation, and elevated expression of the BRIX1 protein as risk factors for the overall survival of CRC patients. CONCLUSIONS: BRIX1 expression is positively correlated with CRC tumor stage; it also acts as a risk factor for the overall survival of CRC patients.