background:non-melanoma skin cancer (nmsc), the most prevalent types being squamous cell carcinoma (scc) and basal cell carcinoma (bcc), is the most common type of malignancy in human beings. these neoplasms are more frequent in the elderly and fair skinned people and mainly occur on sun-exposed sites of the body. ultraviolet b (uvb) has a well-known effect in induction and promotion of growth ...

background & objective: the current approaches to reduce the risk of colorectal carcinoma are through the detection and removal of the precursor lesion” adenomatous polyps”. the study was conducted to evaluate the immunohistochemical expression of p53 and bcl2 in colorectal adenomas and carcinomas. patients and methods: a total of 86 cases, 33 colorectal adenomas, 33 colorectal adenocarcin...

background and objective: evaluation of tumor proliferative activity may provide a predicting parameter to estimate biologic aggression and a subsequent prognosis that has been evaluated in many malignancies. we have selected renal cell carcinoma (rcc) in this study. to determine tumor proliferative activity, ki67 antibody was applied and results were compared with apoptosis, applying p53 antib...

Background & Aims: The role of P53 and proliferating cell nuclear antigen (PCNA) genes in inflamed and non-inflamed odontogenic cysts is related to cell proliferation but it is unclear. The aim of this study was immunohistochemical evaluation of P53 and PCNA expression in inflamed and non-inflamed dentigerous cysts Methods: In the present study, 23 dentigerous cysts (12 inflamed and 11 non-infl...

Transgenic mice expressing simian virus 40 large T antigen in enterocytes develop intestinal hyperplasia that progresses to dysplasia with age. Hyperplasia is dependent on T antigen binding to the retinoblastoma (pRb) family of tumor suppressor proteins. Mice expressing a truncated T antigen that inactivates the pRb-family, but is defective for binding p53, exhibit hyperplasia but do not progre...

Many diverse tumors contain cells that select for mutations at the p53 gene locus. This appears to be the case because the p53 gene product can act as a negative regulator of cell division or a tumor suppressor. These mutations then eliminate this activity of the p53 gene product. The simian virus 40 (SV40) large T antigen binds to p53 and acts as an oncogene to promote cellular transformation ...

Colorectal cancer is the third most common in men and second women globally. There a marked variation incidence of colorectal carcinoma worldwide, where western countries having high rate compared to others. p53 tumour suppressor gene one intensively studied markers tumours. Two were used, (oncoprotein p53) CEA (carcinoembryonic antigen) study. The 102 cases paraffin-embedded samples processed ...

Background: P53 tumor suppressor gene mutation is one of the most common genetic alterations in human malignancies. The mutated from of the gene is stable and can be detected with immunohistochemistry methods. There is much controversy about the expression rate of this gene in malignant melanoma. Objective: To determine the frequency of the P53 antigen expression by sex, age, type and thickness...

BACKGROUND JC virus (JCV) is a polyomavirus that causes progressive multifocal leukoencephalopathy (PML) in humans and is highly oncogenic in experimental animals. Transgenic mice with JCV T-antigen develop cerebellar tumors, which resemble human medulloblastomas, containing two distinct cell subpopulations, T-antigen positive and negative. In T-negative clones, a novel mutant p53 was detected ...

statement of problem: odontogenic keratocysts (okc) make up 10-12% of all developmental cysts with dental origin. okcs are classified into parakeratotic and orthokeratotic types, with completely different clinical features. in order to investigate biological behavior of okcs, an immunohistochemical study was designed, using ki-67 antigen as proliferation marker and p53 protein as tumor suppress...