Endometrial cancer is the most common gynaecological cancer in western countries, being the endometrioid tumours the most common subtype. Most patients are diagnosed at an early stage and present an excellent prognosis. However, a consistent number of those continue to suffer recurrence, without means to be identified by risk classification systems. Thus, finding a reliable marker to predict recurrence becomes an important unmet clinical issue. ALCAM is a cell–cell adhesion molecule, member of the Immunoglobulin superfamily, which has been associated to the carcinogenesis of many cancers. In here, we first determined the value of ALCAM as marker of recurrence in endometrioid endometrial cancer by conducting a retrospective multicenter study in 174 primary tumours. In early stage patients (N=134), recurrence-free survival was poorer in patients with ALCAM-positive compared to ALCAM-negative tumours (HR 4.237; 95%CI 1.01-17.76). This difference was more significant in patients with early stage moderately-poorly differentiated tumours (HR 9,259; 95%CI 2.12-53.47). In multivariate analysis, ALCAM-positivity was an independent prognostic factor in early stage disease (HR 6.027, 95% CI 1.41-25.74). Then, we demonstrated in vitro a role for ALCAM in cell migration and invasion by using a loss-of-function model in two endometrial cancer cell lines. Moreover, ALCAM depletion resulted in a reduced primary tumour size and reduced metastatic local spread in an orthotopic murine model. Gene expression analysis of ALCAM-depleted cell lines supported that motility, invasiveness, cellular assembly and organization were the most deregulated functions associated to ALCAM. Finally, we evidenced some of the downstream effector genes that are involved in ALCAM mediated cell migration; specifically FLNB, TXNRD1 and LAMC2 were validated. In conclusion, our results highlight the potential of ALCAM as a recurrent biomarker in early stage endometrioid endometrial cancer and point to ALCAM as an important molecule in endometrial cancer dissemination by regulating cell migration, invasion and metastasis.
Overall design: Total RNA from two endometrial cancer cells, Ishikawa and Hec1a, with shALCAM and ShControl stably transfected vectors was analyzed in triplicates.
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