Oral Lichen Planus (OLP) is a T-cell-mediated autoimmune disease, with the reticular type being the most common among its subtypes, while the erosive type is known to have a relatively higher risk of malignant transformation. The reticular subtype of OLP has a low risk of malignancy, whereas the erosive subtype has a higher risk, leading to a debate on whether OLP should be considered a precancerous lesion. On the other hand, Oral Squamous Cell Carcinoma (OSCC) is the most common malignant tumor occurring in the oral cavity. It often originates from precancerous lesions, and due to its often unclear early symptoms, there is a growing need for early diagnosis. This study aims to identify salivary biomarkers associated with malignant transformation from OLP to OSCC through a literature review. The review was conducted using the PubMed and Google Scholar databases, focusing on the last 20 years. The search keywords used were "Oral lichen planus reticular," "Oral lichen planus erosive," "Oral squamous cell carcinoma," and "Biomarker." Compared to healthy controls, a total of 48 biomarkers showed increased or decreased expression in OLP-reticular, 43 in OLP-erosive, and 54 in OSCC. There were 27 common biomarkers between OLP-reticular and OLP-erosive, and 11 common biomarkers between OLP-erosive and OSCC. Nine biomarkers were common across OLP-reticular, OLP-erosive, and OSCC. Among the 27 biomarkers showing a shift from OLP-reticular to OLP-erosive, TNF-α, IL-1β, IL-6, IL-8, and TBARS were observed to increase in expression as the condition progressed from OLP-reticular to OLP-erosive. The nine biomarkers involved in the transition from OLP-reticular to OLP-erosive and subsequently to OSCC were TNF-α, IL-1α, IL-1β, IL-6, IL-8, CD44, MMP-9, Catalase, and Survivin. Notably, Survivin was found to decrease in expression in both OLP-reticular and OLP-erosive compared to healthy controls, but its expression increased in OSCC, making it the most noteworthy biomarker.

Oral lichen planus (OLP) is a chronic inflammatory disease observed in approximately 0.5–2.2% of the population, and it is recognized as a premalignant lesion that can progress into oral squamous cell carcinoma (OSCC). The rate of malignant transformation is approximately 1.09–2.3%, and the risk factors for malignant transformation are age, female, erosive type, and tongue site location. Malignant transformation of OLP is likely related to the low frequency of apoptotic phenomena. Therefore, apoptosis-related genetic factors, like p53, BCL-2, and BAX are reviewed. Increased p53 expression and altered expression of BCL-2 and BAX were observed in OLP patients, and the malignant transformation rate in these patients was relatively higher. The involvement of microRNA (miRNA) in the malignant transformation of OLP is also reviewed. Because autophagy is involved in cell survival and death through the regulation of various cellular processes, autophagy-related genetic factors may function as factors for malignant transformation. In OLP, decreased levels of ATG9B mRNA and a higher expression of IGF1 were observed, suggesting a reduction in cell death and autophagic response. Activated IGF1-PI3K/AKT/mTor cascade may play an important role in a signaling pathway related to the malignant transformation of OLP to OSCC. Recent research has shown that miRNAs, such as miR-199 and miR-122, activate the cascade, increasing the prosurvival and proproliferative signals.

Development of squamous cell carcinoma around dental implants is an uncommon clinical manifestation with only a few cases described in the literature. Recently, we observed primary squamous cell carcinoma that developed from leukoplakia around dental implants. We report this case to emphasize the importance of careful oral examination, for implant surgery has to be preceded by thorough evaluation of oral mucosal conditions.