Biochemical Changes of Extracellular Proteoglycans in Squamous Cell Laryngeal Carcinoma

Larynx is a complicated organ with peculiar properties, having a noticeable impact in vocal and respiratory physiology. In squamous cell laryngeal carcinoma, the extracellular matrix components underwent significant modifications concerning their fine chemical structure. Degradation of aggrecan is observed, whereas versican and decorin amounts are increased. The expression of aggrecan is almost totally ceased in later cancer stages, whereas decorin is expressed in normal and cancerous samples. But its expression is increased in cancer, being related to cancer stage. However, the expression of versican seems to be characteristic of the tumor, since none or traces expression is observed in normal samples. Chondroitin/dermatan sulfate is the major glycosaminoglycan, but its sulfation shows a shift from C6 position of galactosamine in normal samples to C4 in malignancy. Dermatan sulfate represents minor amounts in normal samples but increases in proportion up to one-fourth of total sulfated glycosaminoglycans in malignancy. In addition, an increase in the amounts of hyaluronan is also observed in malignant samples. Accumulated data demonstrate that tumor progression is closely related to the alteration of the expression and biochemical composition of specific extracellular constituents that describes the mild aggressive phenotype of squamous cell laryngeal carcinoma.