P53 Mutation in Ovine Pulmonary Adenomatosis

P53 is a protein which is related to DNA, and has been called tumor suppressor, and is coded in human by the gene TP53(1). This protein plays a vital role in complex organisms, and regulates cell cycle. It functions as tumor suppressor to prevent occurrence of cancer. P53 is called genome protector or arrowhead of genome protection or head of genome watchers, all of which indicate its protective role in prevention of genome mutations(2). P53 mutations are the most frequent individual genetic changes in cancers. Acquired mutations in P53 gene are found in all main types of cancer. Among the best points to study mutations of this gene are the lung malignancies(3). Therefore, in this study, we studied changes of this gene in ovine pulmonary adenomatosis. In this study, 5300 lungs were studied in slaughterhouses of Kurdistan, of which some had white, white-turquoise or nodule-like lesions like those seen in pulmonary adenomatosis (300 samples), which accounted for about 5.6% of all lungs. Of all lungs, samples sized 2*2 cm were isolated and studied under microscope. fifteen cases was positive for ovine pulmonary adenomatosis. Following, positive blocks were colored to study mutation of P53 gene by immunohistochemistry method, of which 6 cases showed mutation. So, frequency of this mutation in positive pulmonary adenomatosis cases was identified to be 40%. Next, positive samples were referred to DNA extraction stage, and then, were sent to GATC Company, Germany, for sequence finding by Sanger’s method using sweep initiator in PCR (two-way reading) method. Based on the results, exon No. 5 was without mutation, intron No. 5 had 27 mutations, exon No. 6 had 6 mutations, and intron No. 6 had 17 mutations, and total number of mutations was 50. Also, the highest number of mutations related to replacement of thymine for adenosine in base No. 201, and in every 6 samples, and followed replacement of by cytosine for adenosine in base No. 223 in 4 samples. This study showed that in ovine pulmonary adenomatosis, like human adenocarcinoma, instances of mutation of P53 gene occur, and these exonic and intronic mutations can cause cancer to occur. In this regard, further studies, particularly those on exons, can be very effective and useful.