Expression of type IV collagen in different histological grades of oral squamous cell carcinoma: an...

The aim of this study was to evaluate the expression of type IV collagen in three histological grades of oral squamous cell carcinoma (SCC) in comparison with that in normal oral mucosa, to determine whether this protein can be used as a marker in early detection of the biological behavior of phenotypically altered cells.

The staining intensity, staining pattern, and distribution mode for type IV were compared among the four groups by two pathologists, and the differences between observers and disease groups were statistically analyzed by Chi-square test or Fisher's exact test.

The type IV staining intensity was more enhanced in well-differentiated (w) SCC than poorly-differentiated (p) SCC (P = 0.004). The staining was more linear (P = 0.001) and continuous (P = 0.003) in early invasive SCCs than in highly invasive SCCs. Its distribution was more continuous in wSCC than in less differentiated SCC (P = 0.003). There were statistically significant differences in the staining intensity between wSCC and pSCC (P = 0.005) or between wSCC and moderately differentiated SSC (P = 0.003) and in the staining pattern between wSCC and pSCC (P = 0.001).

The results indicated that there was a direct relationship between the presence of type IV collagen and the differentiation degree of SCC cells and thus that SCC cells loose their capability to form the basement membrane as they become less differentiated.