Quantitative proteomics reveals that distant recurrence-associated protein R-Ras and Transgelin predict post-surgical survival in patients with Stage III colorectal cancer

Surgical resection supplemented with adjuvant chemotherapy is the current preferred treatment for Stage III colorectal cancer (CRC). However, as many as 48% of patients who undergo curative resection eventually suffer from incurable distant recurrence. To investigate the molecular mechanisms involved in Stage III CRC post-surgical distant recurrence, we identified a total of 146 differentially expressed proteins (DEPs) associated with distant recurrence in Stage III CRC using TMT-based quantitative mass spectrometry. Among these DEPs, the altered expressions of R-Ras and Transgelin were then validated in 192 individual specimens using immunohistochemistry (IHC). Furthermore, Kaplan-Meier analysis revealed that the levels of R-Ras and Transgelin were significantly associated with 5-year overall survival (OS) and disease-free survival (DFS), and multivariate Cox-regression analyses revealed that R-Ras and Transgelin were independent prognostic factors for OS and DFS, respectively. In conclusion, this study identified potential biochemical players involved in distant recurrence and indicates that R-Ras and Transgelin are potential post-surgical prognostic biomarkers for Stage III CRC. This proteomics data have been submitted to Proteome Xchange under accession number PXD002903.