Relation between human papillomavirus positivity and p16 expression in head and neck carcinomas--a tissue microarray study.

Overexpression of p16 has been demonstrated to be strongly related to the presence of HPV16, 18. Squamous cell carcinoma of the head and neck has been shown to be associated with human papillomavirus (HPV) infection. The main aim of this study was to investigate the relationship between HPV presence and p16 expression in a representative collection of 60 head and neck carcinomas by tissue microarrays. The presence of HPV (HPV6, 11-low risk, HPV16, 18-high risk) was detected by applying in situ hybridisation. P-16 protein expression was detected immunohistochemically. HPV6, 11 positivity was observed in 10 out of 60 carcinomas. HPV16, 18 presence was found in 30 out of 60 tumours. P-16 expression was detected in 35 out of 60 tumours. A statistically significant relationship was demonstrated between HPV16, 18 presence and increased expression of p16. Also the HPV6, 11 presence was significantly correlated with p16 immunoreactivity. Additionally, this study demonstrates that it is possible to analyse p16 expression and HPV presence by tissue microarrays.

Altered expression of DNA double-strand repair genes Ku70 and Ku80 in carcinomas of the oral cavity.

The relevance of double-strand DNA repair genes has been demonstrated in several tumours. The main aim of this study was to analyse the expression of the heterodimers Ku70 and Ku80, building regulatory subunits of the DNA-dependent protein kinase in 40 oral carcinomas. Ku70 expression was found in 87.5% of grade 1 and grade 3 tumours and in 82.9% of grade 2 carcinomas. Ku80 presence was noted in 87.5% of grade 1 tumours, 82.9% of grade 2 tumours and in all grade 3 tumours. Ku70-positive cells were present in 90.5% of tumours without and in 80% of tumours with lymphatic metastases. A similar relationship was found for Ku80 expression. Additionally, the expression of Ku70 was highly significantly related to smoking habits. Our results demonstrated that defects of DNA double-strand repair genes play an important role in the tumour progression of oral carcinomas.

Relationship of nm23 expression to proliferation and prognosis in malignant melanomas of the oral cavity.

Twenty-nine cases of oral melanomas were investigated for nm23 and Ki67 antigen expression, as well as for the fraction of tumour cells in S-phase, using immunohistochemical techniques and DNA cytophotometry. Nm23 expression was significantly reduced and Ki67 antigen expression increased in primary tumours with either lymph node or organ metastases in comparison to tumours without metastases. The percentages of Ki67 immunoreactive tumour cells and cells in S-phase correlated positively with each other and negatively with the percentage of nm23-expressing cells. These data argue against a significant growth stimulatory function of the nm23H1 gene product nucleoside diphopshate kinase in the progression of oral melanomas. The functional relevance of nm23 in relation to increased proliferation and metastatic spread is discussed.

Selected parameters of blood coagulation and fibrinolysis prior to and after surgical treatment of squamous cell carcinoma of the oral cavity.

Selected parameters of blood coagulation and fibrinolysis were evaluated in 20 patients with squamous cell carcinoma of the oral cavity (stages T2/4 N0/3 M0). The control group consisted of 10 healthy age-matched men. The clotting time, calcium plasma clotting time, prothrombin time index and fibrinogen levels in the patients were similar to those observed in the controls. Increased fibrin degradation products (FDP) to 480 and 80 microg/min were found in patients before and after surgical treatment, respectively. We conclude that, in patients treated surgically because of carcinoma of the oral cavity, there might be increased activity of the fibrinolytic system both prior to and after operation.

Decreased expression of Ku70/Ku80 proteins in malignant melanomas of the oral cavity.

Ku70/80 are genes responsible for the repairing of DNA double-strand breaks and they function as a regulatory subunit of the DNA-dependent protein kinase. Their expression has not yet been investigated in malignant melanomas of the oral cavity. These tumours are characterized by very poor prognosis and etiology independent of UV-radiation. We investigated 29 malignant melanomas of the oral cavity for the expression of Ku70/80 proteins. Ku70 expression was preserved in 21 out of 29 tumours and the percentage of Ku70-positive cells did not exceed 76%. Ku80 was found in 19 out of 29 tumours and the percentage of Ku80-positive cells peaked at 62%. Correlations between Ku70 and Ku80 expression were lost (p>0.05). We conclude that decreased Ku70/80 expression in malignant melanomas of the oral cavity and loss of correlation between these markers may influence progression of oral melanomas.