Differential proteomic profiling of primary and recurrent chordomas.

Chordomas are locally destructive tumors with high rates of recurrence and a poor prognosis. The mechanisms involved in chordoma recurrence remain largely unknown. In the present study, we examined the proteomic profile of a chordoma primary tumor (CSO) and a recurrent tumor (CSR) through mass spectrum in a chordoma patient who underwent surgery. Bioinformatic analysis of the profile showed that 359 proteins had a significant expression difference and 21 pathways had a striking alteration between the CSO and the CSR. The CSR showed a significant increase in carbohydrate metabolism. Immunohistochemistry (IHC) confirmed that the cancer stem cell marker activated leukocyte cell adhesion molecule (ALCAM or CD166) expression level was higher in the recurrent than that in the primary tumor. The present study analyzed the proteomic profile change between CSO and CSR and identified a new biomarker ALCAM in recurrent chordomas. This finding sheds light on unraveling the pathophysiology of chordoma recurrence and on exploring more effective prognostic biomarkers and targeted therapies against this devastating disease.