Isolated immunohistochemical study of type IV collagen does not clearly define that a lesion is invasive or non-invasive and evaluation of Ln-332 γ2 chain expression (cut-off 5%) may be useful as a marker for description of biological differences and diagnosis of OVC from well-differentiated OSCC, especially in doubtful cases.

Background: Oral lichen planus (OLP) is categorized as premalignant lesion although its malignant potential is a matter of controversy. The objective of this study was to investigate Ki67 expression in OLP, oral epithelial dysplasia and oral squamous cell carcinoma (OSCC). Materials and Methods: Expression of Ki67 was evaluated through immunohistochemistry (IHC) in groups of A (17 cases of epithelial hyperplasia), B (16 cases of OLP), C1 (10 cases of mild epithelial dysplasia), C2 (10 cases of severe epithelial dysplasia), D1 (10 cases of well-differentiated OSCC), and D2 (10 cases of poorly-differentiated OSCC). Results: There was a significant difference in Ki67 expression based on quantitative analysis among the six studied groups as well as group B compared bilaterally with groups C2, D1 and D2 (p< 0.0001). However, there was no significant difference between groups B and C1 or between groups D1 and D2 (p> 0.05). Conclusions: Based on the results of the present study it may not be possible to definitely consider malignant transformation potential for OLP. However, expression of Ki67 was significantly higher in OLP than that of epithelial hyperplasia with no significant difference from that of mild epithelial dysplasia. This should be considered by clinicians to carefully and regularly follow up OLP lesions to detect potential subtle changes at an early stage.

Background: A small number of malignant tumors occur during childhood and adolescence. The frequency of such tumors in these age groups is evaluated in only a few studies. Objectives: We aimed to determine the frequency of head and neck cancers in a population of Iranian children and adolescents. Patients and Methods: The records of patients ≤ 19 years old, suffering from head and neck cancers, were reviewed in the pathology centers of Hamadan province from 1989 to 2009. Patients with central nervous system tumors, thyroid and melanoma were excluded. Data were collected based on age, sex and lesion location and statistical analysis was performed. Results: Among the study population (3368 cases of head and neck cancer), 75 cases (2.22%) belonged to children and adolescents aged between 0 -19. The Mean ± SD age of the patients was 13 ± 5.6 (range: 2 months, 19 years). The most common cancers were non-Hodgkin's lymphoma (23%), squamous cell carcinoma (SCC) (20%), and Hodgkin's lymphoma (14.7%). Malignant oral and maxillofacial tumors account for only 18.7% of all head and neck tumors. Conclusions: Carcinomas were the most common malignant tumors of head and neck observed in this age group. Also, oral cancers in children and adolescents constitute a small percentage of the lesions that were studied

-1) is not a good immunohistochemical marker to assess invasion status and differentiate OVC from well-differentiated OSCC; also, it cannot be used as a diagnostic tool to distinguish between variants of OSCC with similar grade.

Human papillomavirus (HPV) infection has implicated in the development of some of the oral/oropharyngeal cancers. However, controversy still exists regarding the prevalence of oral HPV (OHPV) and its risk factors. This study aimed to determine the prevalence and variables of OHPV infection in a healthy Iranian population. This study evaluated 300 oral rinse samples. Following the oral and dental examination of participants and filling out a self‐administered questionnaire; samples collected by swishing and gargling 0.09% saline. The viral DNA extraction, polymerase chain reaction and HPV genotyping then performed. Prevalence of OHPV DNA/OHPV+ infection and OHPV genotypes was 12% and 1% (two cases of HPV6 and one case of HPV53), respectively. Comparison of variables between OHPV+ and OHPV− groups revealed that only income (P = .045), number of cigarettes smoked per day (P = .002), and number of teeth in the mouth (P = .005) were significantly different between the two groups. In conclusion, prevalence of OHPV+ infection and its genotypes were very low in our healthy Iranian population, and its association was not significant with the majority of suggested risk factors. Further studies with a larger sample size are recommended to determine OHPV infection risk factors.

According to the findings of this study, β-catenin and CD44 can differentiate between behavior of OLP and OSCC, while the precancerous nature of OLP and malignant transformation potential of it are not suggested.

Objective: Cell-cell adhesion molecules play an essential role in cell growth and differentiation. β-catenin and CD44s are two adhesion molecules which their expression changes are correlated to loss of differentiation and gain of an invasive epithelial phenotype. Oral squamous cell carcinoma (OSCC) is the most common malignancy of oral cavity. Aim of this study was to compare β-catenin and CD44s expression in different histopathological grades of OSCC. Methods: β-catenin and CD44s expression were evaluated in 10 well differentiated OSCC (group A) and 10 moderately/poorly differentiated OSCC (group B) using immunohistochemistry. Results: β-catenin membranous and nuclear/cytoplasmic expression were significantly different between groups A and B. CD44s membranous expression was insignificant amongst the two groups. Conclusion: Expression of β-catenin and CD44s alter in different histopathological grades of OSCC. It seems that more rate of aberrant cytoplasmic and/nuclear expression and less membranous expression of β-catenin can lead to significantly lower degree of cell differentiation in OSCC.

A lack of knowledge about biopsy techniques and the management of biopsy specimens can cause artifacts. Artifacts are false structures that change the normal morphological and cytological features of tissues. This review article aimed to familiarize clinicians / dentists / surgeons with the factors causing artifacts and with the efficient strategies to prevent or minimize their occurrence. Non-adherence to several rules can result in the formation of artifacts. The clinician's performance during and after the surgical procedure (until the sample is received by the laboratory) may damage the biopsy specimen or make it susceptible to damage. Artifacts may not be clinically considered noteworthy. However, by modifying the histopathological features of the specimen, they can lead to serious errors in the interpretation of lesions. Knowledge on the part of clinicians / dentists / surgeons regarding the factors and potential conditions that can lead to artifacts can decrease the risk of their occurrence, and considerably help pathologists and patients by paving the way for a correct diagnosis, and consequently an appropriate treatment plan.