Immunohistochemistry Optimisation of Some Tumour Suppressor Genes in Chronic Obstructive Pulmonary Diseased Formalin Fixed Paraffin Embedded Tissue Sections.

Abstract

Immunohistochemistry (IHC) technique is one of the antigen-antibody techniques that has added advantage of providing an on-site information in an intact tissue, thus its preferred adoption for diagnosis in the management and treatment of chronic diseases such as COPD and lung cancer. The use of IHC technique has been shown to be very useful in expressing tumour suppressor genes such as p53, particularly in studies for lung carcinogenesis. This study isaimed at carrying out preliminary IHC optimisation for the following tumour suppressor genes; p53, TTC5, Bax and p21 genes on COPD tissue sections, in order to arrive at optimum IHC staining condition and antibody concentrations as part of larger studies on understanding the role of these genes in lung carcinogenesis and consequently, finding better therapy for lung cancer. Several IHC staining using the avidin-biotin complex kit (ABC) were carried out to express the four genes using different staining conditions and different primary antibody dilutions. Our study revealed high-level expression of the four tumour suppression genes on COPD tissue sections with 1:250, 1:500 1:500 and 1:100 optimum primary antibody dilutions for p53, TTC5, Bax and p21 genes respectively. All experiments for optimum results were carried out under 21 ⁰ C room temperature, as higher background staining was seen to be associated with higher environmental staining temperature. These findings revealed an active DNA damage response, even though we are still far from understanding the current function of p53 and its downstream genes in this particular tissue.