RESUMEN
INTRODUCTION: Malignant transformation of Oral Lichen Planus (OLP) remains a much discussed but very less understood realm. Various hypotheses and theories have been put forward to explain the same. Malignant transformation is a complex interplay of epithelial mesenchymal factors acting in tandem. This study tries to identify and asses the stromal changes that pave the way for epithelial migration using Cathepsin B (CB) a cysteine protease belonging to the Cathepsin family. Various studies have been done to study its role in human cancers which have proven that CB helps mark and identify tissue digestion. AIM: The purpose of this study was to evaluate the expression of CB, in OLP and examine its possible role in malignant transformation. MATERIALS AND METHODS: Immunohistochemical analysis of CB expression was done in 50 OLP tissues along with 10 normal mucosa tissue and 10 Oral Squamous Cell Carcinoma (OSCC) cases (control groups). Evaluation was done on the basis of intensity of staining. The intensity was graded in all the cases by assigning values of 0 to 4 in ascending order. Two other observers evaluated the staining and intensity independently and the average of the observations was taken. RESULTS: A variable staining pattern in both the stroma and the cytoplasm of the epithelial cells was noticed. The staining intensity was clearly increased in OLP tissues when compared to normal control tissue and OSCC which served as our positive control. The staining patterns in tissues of OLP and OSCC to Cathepsin B were similar. The staining intensity of Cathepsin B was observed to be increased in both these groups of tissues. CONCLUSION: This study demonstrated a significantly increased expression of CB in OLP. This may be correlated to a possible indicator for its eventual malignant transformation. This overexpression of CB amounts to an array of stromal changes that take place and different mechanisms that get activated underneath the epithelium leading to the formation of what is known as a tumour microenvironment, a well proven entity. We hypothesize that it is this which felicitates the invasion of the overlying epithelial cells.
RESUMEN
BACKGROUND: In recent years, the techniques used to identify human remains post accidents, trauma or in case of criminal investigation have been expanded, improved and rendered more complex by the emergence of technologies based on deoxyribonucleic acid (DNA) analysis. In the head and neck area, tooth has been proven to be the best quantitative source for DNA but in certain cases where the mandible specimen is edentulous or the tooth is extensively destroyed with caries, large dental restorations, mobile, or if they show any perimortem or postmortem fractures, sampling of such tooth specimen is usually avoided. In such situations, bone is considered the next best site for DNA analysis. Mandible being the largest, strongest and dense cortical bone is the most prominent facial bone that can be easily disarticulated. It can be analyzed for the best short tandem repeat (STR) segment qualitative amplification using polymerase chain reaction (PCR) technique for forensic analysis which can be used for gender and age determination. AIM: The aim of this study is to determine the best site for optimum quantitative and qualitative yield of DNA for amplification using specific and standard STR segment by conventional PCR technique. METHODOLOGY: Fifteen mandibular samples exposed to different environmental conditions were collected. Bone pieces of 1 cm × 1 cm were cut from each mandible from three sites, i.e., the ramus, angle and body, wherein the genomic DNA was isolated and was subjected to PCR using restricted number of 25 cycles. RESULTS: The STR segment D3S1358 from clone RP11-438F9 used for the study showed very good amplification in restricted number of PCR cycles in the ramus region with number of repeats in every 15th genomic region. CONCLUSION: This study highlights the use of mandibular bone for the expeditive human identification. As per the study, the ramus of the mandible gave high quantitative and qualitative yield of DNA with thick amplification band of the STR segment as compared to the body and angle of the mandible. Thus ramus of the mandible can be preferred over other sites for molecular forensic investigations.