Expression of fibroblast growth factor receptor substrate 2 (FRS2) in primary retroperitoneal liposarcoma and its clinical implications.

OBJECTIVE

The aim of this study was to investigate the expression level of fibroblast growth factor receptor substrate 2 (FRS2) in tissues of patients with primary retroperitoneal liposarcoma (PRPLS) and its correlation with recurrence and prognosis.

PATIENTS AND METHODS

The pathological specimens, medical records, and follow-up information of patients with PRPLS who underwent radical surgery for the first time in our hospital from January 2013 to December 2016 were retrospectively analyzed. FRS2 protein expression in tissues was determined by immunohistochemistry staining, and the FRS2 protein positive rates in patients with different clinicopathological features were compared. Factors influencing patients' recurrence and survival were determined using the multivariate Cox stepwise regression model.

RESULTS

This research enrolled 87 patients with PRPLS, with the number of cases presenting FRS2 protein positive rate and positive rate in pathological tissues accounting for 62.07% (54/87) and 37.93% (33/87), respectively. The positive expression of FRS2 protein varied markedly among patients with different pathological types, FNCC, LCC grade, number of tumors, positive margin, and recurrence and metastasis (with vs. without) (all p<0.05). The 87 patients were followed up for 3.5-102 months (median, 27.5 months), with a postoperative 5-year overall disease-free survival (DFS) rate of 17.24% [median progression-free survival (PFS): 24.7 months] and a 5-year overall survival (OS) rate of 44.83% (median OS: 47.3 months). Kaplan-Meier survival curves revealed significantly shorter PFS and OS in patients with positive FRS2 protein expression vs. those with negative FRS2 protein expression (χ2=6.396, 5.032, p<0.05). According to the univariate analysis, the 5-year overall DFS rate varied significantly among patients with different pathological types, Fédération Nationale des Centres De Lutte Contre le Cancer (FNCLCC) grades, number of tumors, positive margin, and FRS2 protein expression (all p<0.05). Pathological type, FNCLCC grading, tumor number, recurrence and metastasis, positive margin, and FRS2 protein expression were significantly correlated with the 5-year OS rate of patients (all p<0.05). Furthermore, pathological type, FNCLCC grading, multiple tumors, positive margin, and FRS2 protein expression were identified by multivariate Cox regression analysis to be independent factors that affected patients' 5-year DFS and OS rates (all p<0.05), and that relapsed and metastasized patients had a 4.586-fold risk of death than those without recurrence and metastasis.

CONCLUSIONS

FRS2 shows a high positive rate in the tissues of PRPLS patients and is significantly related to the prognostic recurrence and survival of patients, with potential value in judging the prognosis of patients.