Exploration of the genomic landscape of a long-term surviving stage III colorectal cancer patient identifies recurrent and rare mutations: a case report

A 40-year old female patient from the Chinese Han population presented colorectal cancer (CRC) related symptoms including abdominal discomfort, tenesmus and severe back pain, and was admitted to the First Affiliated Anhui Medical University in October, 2008. The size of her tumor was 3 cm × 3 cm, and the carcinoma had invaded the serosa layer, covering 3/4 of the intestine tube. She was diagnosed with stage III CRC after examination. The patient presented a good prognosis with over 8-year survival after curative surgery and adjuvant therapy with Oxaliplatin and Huaier granules, a traditional Chinese medicine. Using the whole-genome sequencing (WGS) data, we profiled the germline and somatic mutations and obtained an all-inclusive data of the genomic alterations. The genomic alterations were compared with those of stage III CRC patients in The Cancer Genome Atlas Network (TCGA). Mutations in APC, TP53, KRAS, SMAD4, FBXW7 and PIK3CA defined as drivers in TCGA patients were not recorded in our study. However, mutations in MUC4, MUC16, ARID1B, BAZ1A, BRCA2, CTNND1 and NCOA2 rarely reported in TCGA patients were predominant in our patient. Additionally, we observed loss of heterozygosity (LOH) in POLE, RET, BMPR1A, NCOA4 and 30 other genes in contrast to deletion and amplification events recorded in TCGA patients. Overall, we produced a genomic mutation profile of a long-term surviving CRC patient and identified recurrent and rare mutations that could provide a valuable resource for further study into the alterations that characterize advanced CRC which may be useful to design clinical therapy for personalized medicine.