Bernardo Venegas

Histological and molecular aspects of oral squamous cell carcinoma (Review).

Oral squamous cell carcinoma (OSCC) represents 95% of all forms of head and neck cancer, and over the last decade its incidence has increased by 50%. Oral carcinogenesis is a multistage process, which simultaneously involves precancerous lesions, invasion and metastasis. Degradation of the cell cycle and the proliferation of malignant cells results in the loss of control mechanisms that ensure the normal function of tissues. The aim of the current review is to present the histopathological features of OSCC, including potentially malignant changes, the international classification of tumors, the tumor invasion front and tumor biomarkers (Ki-67, p53, homeobox genes and collagen type IV), as well as the tumor microenvironment and function of cancer-associated fibroblasts in the most common type of oral cancer that is encountered by dental surgeons. In OSCC, associations have been identified between the proliferation, basal lamina degradation and connective tissue modulation. Therefore, the comparison of these factors with the survival time of OSCC patients from the histopathological diagnosis is of interest.

Chronic Restraint Stress in Oral Squamous Cell Carcinoma

Pathogenic processes have been identified that could associate chronic stress and cancer, but these findings have not been observed in oral cancer. This study examined the role of chronic restraint stress on the incidence and severity of OSCC induced with 4-nitroquinoline-1-oxide (4-NQO) in the tongues of CF-1 mice. One hundred twenty CF-1 male mice were divided into 4 groups: (A) received two treatments — restraint stress and induction of chemical carcinogenesis (n = 50); (B) induction of chemical carcinogenesis, without restraint stress (n = 50); (C) restraint stress (n = 10); and (D) control (n = 10). After 30 weeks, tongues were dissected and analyzed by conventional histopathology. The severity of OSSC was analyzed according to the International Histological Classification of Tumors and Bryne’s Multifactorial Grading System for the Invasive Tumor Front (ITF). Chronic stress induction was confirmed by plasma corticosterone levels. Results showed that chronic stress was induced with movement restriction (p ≤ 0.05, Mann-Whitney U-test). However, chronic stress did not increase the incidence (p > 0.05, Chi-square) or severity (p > 0.05, Mann-Whitney U-test) of the 4-NQO-induced OSSC in the tongues of CF-1 mice. These results suggest that there is no relationship between chronic stress (induced in mice by restraint) and the incidence and severity of OSSC.

Progressive Extracellular Matrix Disorganization in Chemically Induced Murine Oral Squamous Cell Carcinoma

Introduction. Oral squamous cell carcinoma (OSCC) is one of the ten most common cancers affecting the human population. Tumor pathogenesis implies a multistep process in which cells acquire features that enable them to become tumorigenic and ultimately malignant. The process of OSCC carcinogenesis can be reproduced in animal models, the OSCC induction with 4-nitroquinoline-1-oxide (4NQO) in mice is a widely used tool for studying tumor pathogenesis. Objective. The aim of the present study was to determine the progressive changes in basal lamina and connective tissue remodeling during 4NQO-induced OSCC carcinogenesis. Material and Methods. Samples were classified according to “International Histological Classification of tumors” in mild, moderate, and severe dysplasia and invasive carcinoma. Five samples of each pathologic entity and control healthy tongues were used. Immunohistochemical analysis of collagen IV as well as histochemical analysis of glycosylated molecules (PAS) and collagen I (Picro Sirius red) were performed. Results. During experimental-induced carcinogenesis by 4NQO a progressive basal lamina destruction and collagen I disorganization in adjacent connective tissue can be observed. Conclusion. Our results confirm previous studies that show alterations in extracellular matrix (ECM) in malignant lesions, validating the experimental carcinogenesis induced by 4NQO.

Oral diseases: a 14-year experience of a Chilean institution with a systematic review from eight countries

Background Retrospective studies to assess the distribution of oral diseases (ODs) are helpful in estimating the prevalence of oral diagnoses in the population, and thus help in preventive and curative services. Prevalence and frequency data for ODs are available from many countries, but information from Chile is scarce. Material and Methods This study investigated the frequency of ODs in a Chilean population. For this, we included all patients treated at the University of Talca (UTALCA, Chile) between 2001 and 2014. Patient characteristics were retrieved from medical files. To contextualize our results, we conducted a systematic review (SystRev) using Publish or Perish software (PoP), Google Scholar and MEDLINE/PubMed. Results One hundred sixty-six ODs were diagnosed, and the most prevalent groups were soft tissue tumours, epithelial pathology and salivary gland pathology. Individually, irritation fibroma, oral lichen planus (OLP) and mucocele were the most common diagnoses. ODs frequently affected unspecified parts of the mouth (including cheek, vestibule and retromolar area), gum, lips, tongue and palate. In the SystRev, the more studied diagnoses were leukoplakia, OLP and recurrent aphthous stomatitis; prevalent lesions included Fordyce’s spots, recurrent aphthous stomatitis and fissured tongue. Chilean patients and SistRev shared almost all ODs. Conclusions The results reflect ODs diagnosed in a specialized service of oral pathology and medicine in Chile and will allow the establishment of preventive/curative policies, adequate health services and dentistry curriculum. Key words:Stomatognathic diseases, mouth diseases, oral mucosal lesions, epidemiology, Chilean population, retrospective cohort study.

Oral pemphigus vulgaris after Chilean earthquake.

A 62-year-old male, was referred for the management of extremely painful oral ulcerations. He reported that ulcers began after the Chilean earthquake in 2010. His medical history was not significant. Ulcerations showed remissions and exacerbations since earthquake. On clinical examination, skin and other sites involvement was not found. An incisional biopsy was taken from the cheek region. Histopathological examination revealed suprabasilar blister formation associated with acantholysis. Hence, a final diagnosis of oral pemphigus vulgaris was made based on histopathological pattern and clinical features. Treatment regimen included oral prophylaxis; prednisone and betamethasone 3–4 times daily for topical application. The patient was controlled every 2 weeks for the first 1 month. The lesions had diminished and increased healing with steroids within 4 weeks of starting the treatment. The patient was kept under observation for 12 months and the lesions showed signs of recurrence. Lichen planus is a chronic inflammatory disease that affects the skin and the mucus membrane. Oral lichen planus (OLP), presents frequently in the fourth decade of life and affects women more than men in a ratio of 1.4:1. OLP is a T-cell mediated autoimmune disease in which the auto-cytotoxic CD8+ T cells trigger apoptosis of the basal keratinocytes (KCs) of the oral epithelium through tumor necrosis factor (TNF)-α, Fas–FasL mediated or granzyme B activated apoptosis. Recent evidence suggests that anxiety, depression, and psychological stress are correlated with the occurrence and intensity of associated OLP symptoms. OLP is a condition that has no cure, reporting 1% of malignization. The treatment in most cases is palliative because of OLP recalcitrant nature. Topical treatment is recommended mainly because of minimal side-effects.