DIAGNOSTIC AND PROGNOSTIC SIGNIFICANCE OF STROMAL MYOFIBROBLASTS IN LARYNGEAL CARCINOGENESIS

Abstract

Background. Recent studies have shown that stromal reaction in cancer has a more important diagnostic and prognostic significance than previously thought. CD34-positive stromal cells and myofibroblasts may play an important role in host response to invasive cancer. The aim of our studies was therefore to analyze the distribution and immunohistochemical phenotype of stromal cells in epithelial hyperplastic lesions (EHL) and squamous carcinoma (SC) of the larynx, and to establish their diagnostic and prognostic significance.Methods. We investigated samples of 62 resected larynxes with SC, 50 laryngeal biopsies of EHL and SC, and 5 samples of normal laryngeal mucosa. Immunohistochemistry was performed using antibodies against vimentin, a-smooth muscle actin (SMA), desmin, CD34 and leucocyte common antigen (LCA).Results. The stroma of normal laryngeal mucosa and EHL contained scattered CD34-positive cells, but there were no SMApositive myofibroblasts. In contrast, the stroma of SC contained SMA-positive cells but there were no CD34-positive stromal cells. We observed two patterns of stromal reaction in SC: one was characterised by a marked proliferation of myofibroblasts and desmoplasia, with scarce lymphocytic infiltration; this pattern tended to be associated with well or moderately differentiated SC. The other was characterised by few myofibroblasts, weak desmoplasia, and dense lymphocytic infiltration; the latter pattern tended to be associated with moderately or poorly differentiated SC.Conclusions. Our studies show that disappearance of CD34positive cells and appearance of SMA-positive myofibroblasts in the stroma is associated with transformation of laryngeal EHL to SC. This pattern of stromal reaction should be regarded as an additional marker of invasion. Our results also suggest that characteristics of stromal reaction in SC could be of prognostic significance.</p