EXPRESSION OF KERATIN-13, KERATIN-14 AND KERATIN-19 IN ORAL HYPERPLASTIC AND DYSPLASTIC LESIONS FROM SUDANESE AND SWEDISH SNUFF-DIPPERS - ASSOCIATION WITH HUMAN-PAPILLOMAVIRUS INFECTION

Changes in the expression of keratins (1%), indicating disturbed tissu e differentiation is one possible marker of malignant potential in str atified squamous epithelia. The presence of human papillomaviruses (HP Vs) in the epithelium of the uterine cervix is increasingly regarded a s a marker of risk for cervical cancer: However, a similar role in ora l cancer and precancer remains controversial To address these question s potentially malignant oral mucosal lesions from Sudanese (9 hyperpla sias/40 dysplasias) and Swedish (15 hyperplasias) snuff-dippers were e xamined by immunohistochemistry for expression of K types 13, 14 and 1 9 using monoclonal antibodies directed against each. HPV infection was searched for by in situ hybridization (ISH) using the cocktail HPV Om niProbe and the ViraType probe. For the Sudanese lesions moderate to i ntense expression of both K13 (basal, basal/intermediate, basal/interm ediate/superficial and intermediate/superficial cell layers) and K14 ( basal, basal/intermediate cell layers) was found in 49/49 (100%). For the Swedish lesions weak to moderate expression of K13 (basal, basal/i ntermediate, basal/intermediate/superficial cell layers) and K14 (basa l cell layer) was found in 12/15 (80%) and 10/15 (67%), respectively I n the Sudanese lesions, expression of K13 showed a distinct pattern th rough the oral mucosa and its verrucous projections, with an increase towards the superficial cell layers of dysplastic, but not hyperplasti c epithelium. K19 was expressed in the basal cell layer in 16/49 (33%) of the Sudanese lesions, while all the Swedish lesions were negative. HPV was found in only 2 Sudanese cases, bath of which harboured both type 6 and type 11: both these cases demonstrated mild epithelial dysp lasia. The present study shows that a) there is a high prevalence of e xpression of both K13 and K14 in oral lesions from Sudanese toombak di ppers indicating dysregulation of keratinocyte maturation b) one-third of the Sudanese oral lesions expressed K19, regarded as a basal kerat in representing epithelial dedifferentiation, which may prove to be a valuable risk marker in follow-up studies c) HPV genome is found infre quently in oral lesions from Sudanese toombak dippers, suggesting that these viruses may not play a prominent role in the early stages of ca rcinogenesis in these subjects. These markers were less often expresse d in the Swedish lesions, consistent with their much lower rate of mal ignant transformation.