EXPRESSION OF CD44 VARIANT EXONS BY PRIMARY AND METASTATIC ORAL SQUAMOUS CARCINOMAS

Abnormal CD44 expression in many neoplasms correlates with behaviour, but reports on its role in oral squamous carcinoma are contradictory, CD44 expression was characterised in a closely matched series of oral carcinomas with and without metastases in both frozen and formalin-fix ed tissue and correlated with behaviour and histological grading param eters. Eleven primary oral squamous carcinomas without metastases and nine primary carcinomas with 19 matched metastases were stained immuno cytochemically for CD44H and products of variant exons v3, v4/5, v6 an d v9. Patterns of staining in frozen and formalin-fixed tissue were co rrelated with invasive front grading and behaviour using exact inferen tial statistics. Most primary carcinomas stained for all exons tested but some showed loss of expression of v4/5. Loss of expression was mor e marked in metastases, but there was no correlation between expressio n and behaviour or grade. Stromal surfaces of epithelial cells often e xpressed variant exon products reflecting loss of polarity. This, toge ther with selective loss of v4 and a 5 in primary carcinomas and their more frequent loss in metastases, suggests that CD44 may play a role in metastasis of some oral squamous carcinomas.