In the effort to identify novel, relevant prognostic factors for the clinical monitoring of patients affected by squamous cell carcinomas of the oral cavity (SCCOC) we have pursued a molecular screening at the gene and protein level on 166 surgical specimens derived from patients with an accessible clinical history and >2 years follow-up. The screening was focalized on cell surface proteoglycans (PGs) based upon the assumption that altered expression of individual or groups of PGs may predict disease course and therapeutic response, and thereby allow for a clusterization of patients in discrete subsets. The 11 PGs contemplated in the screening and including syndecan-1-4 (SDC1-SDC4), glypican-1-6 (GPC1-GPC6) and NG2, were found to be transcribed at variable levels and with a decreasing frequencies SDC1>SDC4>SDC2>SDC3>GPC4>GPC3>GPC1 >GPC5>CSPG4>GPC6>GPC2. SCCOC cells de novo transcribed GPC2, GPC5 and NG2 and regulated all SDCs, GPC1, -3, -4 and -6, suggesting that an altered surface profile of PG is a characterizing trait of these tumor cells In situ distributional analysis of these PGs on a total of 149 cases revealed many fewer lesions actually translated the molecules which were detected with a frequency range of 14% (SDC2) to 92% (SDC1). Noteworthy was, however, that SDC2 was present in the intra-lesional stroma and in association with neovessels in all the cases, suggesting that this specific PG was a key element of stromal fibroblasts and angiogenic structures. Poor translational efficacy of several of the PGs was accompanied by an apparent retention of the molecules within the cytoplasm of SCCOC cells. This finding suggest that modulated expression of cell surface PGs may be a representative secondary event in SCCOC and that these carcinoma cells do not mount up an effective intracellular machinery for proper shuttling and membrane incorporation of the PGs.
Overall design
A total of 166 surgical specimens of primary SCCOC were collected after informed consent from individuals who underwent surgical removal of the tumor lesions and RNA from 119 surgical specimens were extracted; a pool of RNAs extracted from 5 normal epithelia tissues was adopted as a sample calibrator (HEALTHY sample). cDNA from each samples and from pool of normal epithelial were loaded on TLDA and amplified. HEALTHY sample were amplified 20 times in two replicates (in each TLDA card); each patient sample were amplified 1 time in two replicates and 7 samples of them were loaded two times in a separate TLDA card (for a total of 4 replicates).
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