In Sweden, snu (locally known as snus), was introduced since the year 1637. Presently, Sweden has the highest per capita consumption and sale ®gures of snu in the world, and the habit is becoming increasingly popular. Snus is manufactured into a dry form used in the nasal cavity and a moist form used in the oral cavity. Snus manufactured for oral use is a moist ground tobacco of Dark Kentucky or Virginia species mixed with an aqueous solution of water and other blending ingredients. This form of snu is found in two types: (1) loose and (2) portion-bag-packed. These are the most widely used. The loose moist form (1±2 g a quid) is the most popular type consumed by 73% of the males, followed by the portion-bag-packed form (0.5±1 g a quid), consumed by 13% of the males, while 14% of the males are mixed users. The majority of snus users place the quid in the vestibular area of the upper lip, and the prevalence among persons 15 years of age or older is 15.9% among males and 0.2% among females. The pH of snus has declined from a previous range of 8±9 to a range of 7.8±8.5, moisture content ranges 35±60% and nicotine content is in the order of 5±11 mg/g dry wt tobacco-speci®c N-nitrosamines (TSNAs) in micrograms (N H -nitrosonornicotine: NNN 5±9; 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone: NNK 1±2; N H -nitrosoanatabine: NAT 2±5). In the Sudan, snu, locally known as toombak, was introduced approximately 400 years ago. It is always processed into a loose moist form, and its use is widespread in the country. Tobacco used for manufacture of toombak is of the species Nicotiana rustica, and the fermented ground powder is mixed with an aqueous solution of sodium bicarbonate. The resultant product is moist, with a strong aroma, highly addictive and its use is widespread particularly among males. Its pH range is 8±11, moisture content ranges 6±60% and nicotine content is from 8 to 102 mg/g dry wt, and TSNAs contents in micrograms (NNN 420±1 550; NNK 620±7 870; NAT 20±290). Snus and toombak dippers develop a clinically and histologically characteristic lesion at the site of dipping. Probably due to control of the TSNAs in snus, this type of snu is associated with a lower risk of cancer of the oral cavity (relative risk: RR 5±6-fold), whereas the risk for cancer of the oral cavity among toombak users was high (RR 7.3±73.0-fold). In conclusion, the two snu products signi®cantly dier in many aspects. Most notable dierences are tobacco species, fermentation and ageing, nicotine and TSNAs content, pH, expression of the p53 tumour supressor gene, and keratin types 13, 14, and 19. It was, therefore, the object of the present study to highlight the oral health hazards of toombak, and to compare it with snus regarding the aforementioned dierences. #

Despite the differential expression of S100A14 (a newly identified S100 member) in various human cancers including oral squamous cell carcinomas (OSCCs), its biological role in tumour invasion has not been characterised. The aim of this study was thus to investigate the possible role of S100A14 in OSCC cell invasion. Using immunohistochemistry in normal (n=13), dysplastic (n=10) and OSCC (n=16) archival tissues, S100A14 protein was found to be down-regulated/lost with concomitant membrane to cytoplasmic translocation in OSCCs, especially in the invading tumour islands. These expression data were corroborated by profiling S100A14 mRNA expression using quantitative RT-PCR (qRT-PCR) in an in vitro human OSCC progression model consisting of cell-lines derived from normal (n=3), dysplastic (n=3) and OSCC (n=8) tissues. Employing in vitro Matrigel invasion assay, we demonstrated that retroviral vector mediated over-expression of S100A14 resulted in significant decrease in the invasive potential of OSCC derived CaLH3 and H357 cell-lines whereas siRNA mediated knockdown resulted in significant increase in the invasive potential of CaLH3 cell-line. Pathway focused PCR array and validation using qRT-PCR revealed that S100A14 over-expression was associated with down-regulation of MMP1 and MMP9 mRNAs in both CaLH3 and H357 cell-lines. Further, S100A14 over-expression was found to be associated with suppression of MMP9 gelatinolytic activity in CaLH3 cell-line. Additionally, an inverse correlation between mRNA expression levels of MMP1 and MMP9 with S100A14 was found in 19 cases of OSCCs. Collectively, these data provide the first evidence for a role of S100A14 protein in regulation of OSCC cell invasion by modulating expression of MMP1 and MMP9.

Using PCR/DNA sequencing, we investigated the prevalence of human papillomavirus (HPV), herpes simplex virus (HSV) and Epstein-Barr virus (EBV) DNA in brush biopsies obtained from 150 users of Sudanese snuff (toombak) and 25 non-users of toombak in formalin-fixed paraffin-embedded tissue samples obtained from 31 patients with oral dysplasias (25 toombak users and 6 non-users), and from 217 patients with oral cancers (145 toombak users and 72 non-users). In the brush tissue samples from toombak users, HPV was detected in 60 (40%), HSV in 44 (29%) and EBV in 97 (65%) of the samples. The corresponding figures for the 25 samples from non-users were 17 (68%) positive for HPV, 6 (24%) positive for HSV and 21 (84%) for EBV. The formalin-fixed samples with oral dysplasias were all negative for HPV. In the 145 oral cancer samples from toombak users, HPV was detected in 39 (27%), HSV in 15 (10%) and EBV in 53 (37%) of the samples. The corresponding figures for the samples from non-users were 15 (21%) positive for HPV, 5 (7%) for HSV and 16 (22%) for EBV. These findings illustrate that prevalence of HSV, HPV and EBV infections are common and may influence oral health and cancer development. It is not obvious that cancer risk is increased in infected toombak users. These observations warrant further studies involving toombak-associated oral lesions, to uncover the possible mechanisms of these viral infections in the development of oral cancer, and the influence of toombak on these viruses.

No abstract

In stratified squamous epithelia, altered expression of keratins (Ks) is one possible marker of malignant potential. In the epithelium of the uterine cervix, presence of human papillomaviruses (HPVs) is increasingly regarded as a marker of risk for cervical cancer. However, a similar role in oral cancer and precancer remains controversial. To address these questions, formalin-fixed, paraffin-embedded oral carcinomas from Sudanese snuff dippers (n= 14) and oral carcinomas from Sudanese (n= 14), Swedish (n= 19) and Norwegian (n=41) non-snuff dippers were examined by immunohistochemistry for expression of K types 13, 14 and 19 using monoclonal antibodies. HPV infection was searched for in all the carcinomas by in situ hybridization (ISH) using the cocktail HPV OmniProbe and the ViraType probe. Carcinomas from Sudanese (snuff dippershon-snuff dippers) were also examined for HPV infection by polymerase chain reaction (PCR) using the general HPV primers GP5+/GP6+. For the oral carcinomas from snuff dippers, moderate to intense expression of K13 (71%; 10/14), K14 (86%; 12/14) and K19 (93%; 13/14) was found. For the oral carcinomas from non-snuff dippers, weak to moderate expression of K13 (64%; 47/74), K14 (43%; 32/74) and K19 (45%; 33/74) was found.HPV DNA was not detected in any of the carcinomas from three countries when examined by ISH. The Sudanese (from snuff dippershon-snuff dippers) oral carcinomas were also negative for HPV DNA with the PCR. The present study shows that (i) there is a high level of expression of K13, K14 and K19 in oral carcinomas from snuff dippers compared to those from non-snuff dippers, (ii) this high level of expression may arise from dysregulation of keratinocyte proliferation and maturation caused by damaging effects of snuff, (iii) the HPV genome is not found in Sudanese (snuff dippers/ non-snuff dippers), Swedish or Norwegian oral carcinomas, and (iv) this may suggest that these viruses do not play a prominent role in the aetiology of oral carcinomas from these countries.