Diabetes mellitus is among the most common chronic diseases, with significant and well documented impact on oral cavity health. Among the most common diseases of the oral cavity mucosa and complications in patients with impaired glucose metabolism and diabetes mellitus is oral lichen ruber (OLR), which according to World Health Organisation (WHO) is considered potentially malignant disorder. It was found that lichen ruber in diabetes mellitus has a much more aggressive clinical course in the form of atrophic-erosive and ulcerative lesions showing an increased tendency to malignant transformation. Although OLR etiology is unknown, evidence suggests cell-mediated autoimmune pathogenesis. OLR epithelial cells show anomalies in both enzymatic activity and carbohydrate metabolism, which may be related to hormones regulating carbohydrate, insulin and insulin-like growth factors 1 and 2 (IGF-1 and IGF-2) metabolism. The hypothesis of our research is that patients with diabetes mellitus and oral lichen ruber lesions will have a disturbance of insulin-like growth factors 1 and 2 and hence a greater risk of malignant transformation, compared to patients with oral lichen ruber without diabetes and healthy patients without alterations in the oral mucosa.

Oral lichen ruber (OLR) in the diabetes mellitus patients has more aggressive clinical course in the form of atrophic-erosive and ulcerative lesions showing an increased tendency to malignant transformation. OLR epithelial cells show anomalies in both enzymatic activity and carbohydrate metabolism, which may be related to hormones regulating carbohydrate, insulin and insulin-like Growth Factors 1 and 2 (IGF-1 and IGF-2) metabolism. The role of insulin-like growth factors (IGFs) is of great importance in normal growth and cell development (cell proliferation, differentiation and apoptosis), and is involved in different aspects of cell transformation in malignant phenotype. A change in the expression of IGF1, IGF2 and IGF2R proteins is described in several types of malignant tumors including oral cancer. However, data on their role in the development of malignant lesions of the oral cavity are scarce, and the results are inconsistent. Our hypothesis is that patients with diabetes mellitus and oral lichen ruber lesions will have a disturbance of insulin-like growth factors 1 and 2 and hence a greater risk of malignant transformation, compared to patients with oral lichen ruber without diabetes and healthy patients without alterations in the oral mucosa.

Inclusion Criteria:

• histopathologically confirmed oral lichen ruber patients, with and without diabetes mellitus
• healthy volunteers referred for alveolotomy

Exclusion Criteria:

• non-consent patients

The patients included in the study are patients with oral lichen ruber referred to the Department of Oral Medicine, University of Zagreb. Healthy mucosa samples were taken from healthy volunteers referred for alveotomy of wisdom tooth to the Department of Oral Surgery, School of Dental Medicine, University of Zagreb.