Eur Arch Otorhinolaryngol (1997) 254 (Suppl. 1):S133-S137 9Springer-Verlag 1997 W. Golusinski 9 J. Olofsson 9 Z. Szmeja 9 K. Szyfter W. Szyfter 9 W. Biczysko 9 K. Hemminki Alteration of p53 gene structure and function in laryngeal squamous cell cancer Abstract The p53 gene is known as an anti-oncogene that manifests its function by controlling the cell cycle and is responsible for apoptosis of cells with unrepaired DNA. An accelerated p53 protein synthesis is the first re- sponse of a cell following DNA damage. However, muta- tions of the p53 gene can disturb protein synthesis or may be responsible for synthesis of a changed protein unable to control the cell cycle. Laryngeal tissue specimens from 120 patients were tested by immunohistopathological staining to detect mutated wild-type p53 protein. It was found that p53-positive specimens correlated with TNM staging and histopathological grading. Another indication of entering the cell cycle and undertaking an active prolif- eration by laryngeal cells was shown by detection of pro- liferating cell nuclear antigen (PCNA) and Ki67 nuclear antigen, which appeared in proliferating cells (late G1, S- G2 and M phase), but was absent in resting cells. Scoring of the staining for p53 protein, PCNA and Ki67 correlated with each other. DNA from 40 specimens was then iso- lated, amplified by polymerase chain reaction and analysed by single-strand conformation polymorphism and DNA sequencing for mutation in the p53 gene. Fif- w. Golusinski (N~) 9 Z. Szmeja 9 W. Szyfter Department of Otolaryngology, Karol Marcinkowski University of Medical Sciences, Przybyszewskiego 49, PL-60-355 Poznan, Poland J. Olofsson Department of Otolaryngology, Head and Neck Surgery, Haukeland University Hospital, Bergen, Norway K. Szyfter Institute of Human Genetics, Polish Academy of Sciences, Poznan, Poland K. Hemminki Center for Nutrition and Toxicology, Karolinska Institute, Huddinge, Sweden W. Biczysko Department of Clinical Pathology, Karol Marcinkowski University of Medical Sciences, Poznan, Poland teen DNA samples were found to be positive, while muta- tions were detected in exons 5-8 in 13 samples. The ma- jority of mutations were found in tissue specimens from T3 and T4 tumors. A possible explanation is almost half was attributable to genotoxic effects of tobacco smoking. Changes in the p53 gene and its products may also reflect early changes in laryngeal carcinogenesis and be of prog- nostic value. Key words Laryngeal cancer - p53 gene 9 Cell DNA sequencing- Mutation Introduction Information concerning cell proliferartion and its kinetics is a necessity for an understanding of tumor biology. Oncogenes and tumor suppressor genes play an important role in carcinogenesis because of their involvement in the regulation of the cell cycle. The best-known example is the p53 gene, which is located on the short arm of chro- mosome 17 and normally acts as an effective ("wild- type") tumor suppressor gene. Mutations of the p53 tumor suppressor gene belong to the most common genetic alter- ations in many types of cancer. Such changes of the wild- type gene may result in it developing transforming activ- ity. Inactivation of the gene has been associated with un- controlled cell growth and development of cancer, as manifest by changes in cell morphology and the clonal ex- pansion of cells. According to the molecular mechanism responsible for the initiation of tumorigenesis [10], previously acquired mutation(s) result in cancer-related genes. A cell contain- ing a specific change in a critical gene may thus have a growth advantage and become the dominant cell type in tumor progression. This concept is in accord with the finding that mutated p53 gene products most often were identified in anaplastic and undifferentiated tumors. The occurrence of the p53 gene has been studied ex- tensively in head and neck cancers. Many studies, how- ever, combine cancers from differing sites within the head