Cell-cycle phase progression analysis identifies three unique phenotypes in soft tissue sarcoma

Loddo et al. (Br J Cancer 100:959-70, 2009) established the prognostic significance of cell cycle markers and "Cell-Cycle Phenotypes" in breast carcinoma. This study aims to 1) identify prognostic cell-cycle markers in sarcoma, and 2) assess the prognostic potential of specific cell-cycle phenotypes in sarcoma.

Tissue samples from 128 soft tissue sarcomas were stained for four cell cycle-specific markers: Mcm2, Geminin, Plk1, and H3S10ph. Only primary soft tissue tumors (liposarcoma, leiomyosarcoma, synovial sarcoma, and undifferentiated pleomorphic sarcoma) were included in the analysis. Any tumor coming from a recurrent or metastatic lesion were excluded from the analysis. Three cell-cycle phenotypes (I, II, III) were derived from marker expression patterns. Prognostic significance was evaluated in a subset of primary soft tissue sarcomas using Cox regression for survival analysis.

Compared to phenotype I, the phenotype III tumors had a decreased 5-year overall survival (HR 6.81 [2.36-19.61]; p =  < 0.001), 5-year disease-free survival (HR 1.07 (1.02-1.18); p = 0.004), and 5-year metastasis-free survival (HR 4.34 [1.58-11.93]; p = 0.004). High expression of Plk1 was associated with decreased 5-year overall survival (HR: 4.04 CI [1.21-6.67; p = 0.02) and 5-year metastasis-free survival (HR: 2.91 CI [1.15-7.37]; p = 0.03). Geminin was also found to have a decreased 5-year overall survival (HR:2.84 CI [1.21-6.67]; p = 0.02). No statistical difference in prognostication were noted between phenotypes and the AJCC system.

We identified three unique sarcoma cell cycle phenotypes that have prognostic significance. This performs similarly to the AJCC staging system.