Prognostic impact of histological categorisation of epithelial–mesenchymal transition in colorectal cancer

BACKGROUND: The crosstalk between cancer cells and stroma is involved in the acquired capability for metastasis through the induction of epithelial–mesenchymal transition (EMT). We aimed to clarify the prognostic value of the histological category of EMT in colorectal cancer (CRC). METHODS: Tumour EMT was graded into one of three histological categories on the basis of integrated assessment of poorly differentiated clusters and pro-EMT desmoplasia at the leading edge of the primary tumour (Histology(EMT)). Stage II and III CRC patients (cohort 1, N=500) and stage IV patients (cohort 2, N=196) were retrospectively analysed. RESULTS: In cohort 1, patients were stratified into three groups with widely different disease-free survival rates (95%, 83% and 39%) on the basis of Histology(EMT) (P<0.0001). In cohort 2, Histology(EMT) significantly stratified overall survival of patients irrespective of metasectomy. Multivariate analyses indicated that Histology(EMT) had a strong prognostic impact independent of staging factors. Statistically, Histology(EMT) had a better prognostic stratification power than T and N stages; however, in cohort 2, the power of M substage was superior. CONCLUSIONS: A histological model to categorise EMT by integrated assessment of dedifferentiation and desmoplastic environment is a potent prognostic index independent of staging factors.