Comparative analysis of clonal evolution among patients with right-sided colon cancer, left-sided colon cancer and rectal cancer

Tumor multi-region sequencing reveals clonal evolution which play a key role in progression and metastases of the tumor. However, the comparative analysis among right-sided colon cancer (RCC), left-sided colon cancer (LCC) and rectal cancer (RC) patients as well as the study of lymph node metastasis (LN) with extranodal tumor deposits (ENTD) from evolutionary perspective remain unknown. In this prospective study, we recruited 68 CRC patients with RCC (18), LCC (20) and RC (30). We performed high-depth whole exome sequencing (WES) of 206 tumor regions including primary tumors, LN and ENTD samples. We identified that evolution pattern of LCC and RC was more complex and divergent than RCC, suggesting evolutionary diversity in the initiation and progression of LCC and RC. Genetic and evolutionary evidences found that ENTD was a distinct entity from LN and evolved later. In conclusion, our study showed differences in clonal evolution between RCC with LCC and RC.