**5.5. Smokeless tobacco keratosis and HPV**

mixed non-AE variants) to evaluate the association between OLP variants and HPV-infection. However, this analysis failed to find particular correlation between OLP variants and HPVinfection. Analyzing 82 patients diagnosed with atrophic OLP, Mattila et al. [58] found that HPV-infection was present in 15,9% of lesions and was related with High-risk HPV-16. In addition, the HPV-positive cases presented a higher proliferation index and overexpression of Topoisomerase IIa (protein responsible for removal of DNA positive supercoils) in supra‐

250 Human Papillomavirus and Related Diseases – From Bench to Bedside A Diagnostic and Preventive Perspective

Ostwald et al. [63] studying prevalence and influence of Low-risk Hpv 6/11 and high-risk Hpv16/18 in benign oral lesions and OSCC detected the HPV-infection in 15.4% of OLP cases. Low-risk HPV presented the higher prevalence in OLP, whereas the High-Risk HPV presented the higher prevalence in OSCC. These interesting results demonstrated that High-risk HPV infection was successively increased from low-level premalignant lesion to OSCC, suggesting a correlation between High-Risk HPV and malignant potential [64]. The conflicting results of studies involving HPV-infection and malignant transformation of OLP lesions may occur due to differences in sample size of patients, associated comorbidities, and other external factors.

The name "*Oral submucous fibrosis*" (OSF) was firstly presented by Joshi in 1953; however, Schwartz had described this condition in five cases originated from Kenya, a year before, as '*atropica idiopathica mucosae oris*' [65]. OSF is frequently found in South Asian and South-East Asian patients (India, Bangladesh, Sri Lanka, Pakistan, Taiwan, Southern China) aged of 20– 40 years [63]. This potentially malignant disorder has been close related to chronic consump‐

Microscopically, OSF can be characterized by the submucosal deposition of connective tissue. This deposition is extremely dense and presents a reduced vascular tissue. In early-stage lesion, sub-epithelial vesicles can be observed. On the other hand, the older-stage lesion presents epithelial atrophy with hyperkeratosis. In conjunction with these epithelial changes, 10% to

Although, OSF presents a multifactorial etiology, Betel quid and Paan consumption are considered the major causative agents. In pertinent literature only four studies evaluating the HPV and OSF were found: two studies evaluating an Indian population; one study analyzing differences between HPV-infection prevalence in OCSS and pre-malignant lesion; one study comparing two different HPV detection methods). Study performed by Luo et al. [49] pre‐ sented only two cases of OSF infected by HPV-virion. Although, the lesions had been positive for HPV-infection was not possible to perform other conclusions, because this study used a small number of cases. Chaudhary et al. [66], comparing two HPV-detection methods identi‐ fied around of 27% (total of 208 cases) of OSF patients' positive for HPV-infection. These two reports do not allow us to establish any positive correlation between HPV-infection and malignant transformation. In addition, evaluation of a hundred thirteen cases of OSF, designed by Mehrotra et al. [67], to assess the relationship of human papilloma virus infection and OSF showed no significant correlation between these two entities. Although, the hpv-infection do not show association with OSF an Indian population study, investigating the prevalence of

basal layers in comparison with HPV-negative cases.

**5.4. Oral submucous fibrosis and HPV**

tion of Betel quid and Paan [42].

15% of biopsied tissues present epithelial dysplasia [42].

Several oral manifestations have been associated to use of *Smokeless Tobacco*. Oral manifesta‐ tions occur at the site of Smokeless Tobacco placement including mucosal lesions (Smokeless Tobacco Keratosis "STK") and gingival-periodontal disorders such as gingival recession, gingival inflammation, changes in gingival blood flow and interproximal periodontal attach‐ ment loss [69]. The use of *Smokeless Tobacco* and the STK has been suggested to be involved in development of oral cancers [70].

Clinically, the site of Smokeless Tobacco placement presents a leukoplakic lesion referred as "snuff dippers" lesions [71] STK presents a non-specific histopathologic appearance [42]. Squamous epithelium is hyper keratinized [42,70] and acanthotic; in addition, the intra-cellular edema is not uncommon on superficial cells glycogen-rich. In some cases, subjacent connective tissue can present an amorphous eosinophilic material. An increased sub-epithelial vascularity and vessel engorgement also can be seen. [42]. In STK the epithelial dysplasia does not common. In a study conducted by Leopardi et al. [72] they not evidenced cases of epithelial dysplasia. However, when present, epithelial dysplasia is usually mild [42]. Studies on STK pointed to three clinical grades [73].

Studies on smokeless tobacco keratosis pointed to three clinical grades: 1) Grade I superficial lesions presenting modest wrinkling and no mucosal thickening. Grade I lesions tends to present similar color to the surrounding mucosa. 2) Grade II superficial whitish lesions with undulating areas displaying moderate wrinkling and no mucosal thickening. 3) Grade III white entities with normal mucosal color areas, STK Grade III shows mucosal thickening and wrinkling [71]. However, this lesion is reversible when the product is discontinued [42]. Related to HPV a work aimed to detect p16 (INK4a) protein expression in smokeless tobacco keratosis as reliable precancerous marker. The author detected HPV-DNA in 15 of 62 (24%) cases and an apparent relation between the three standard grades of STK lesions and HPVinfection was observed. [71]
