Promoter methylation of death-associated protein kinase and its role in irradiation response in cervical cancer.

This study was aimed at investigating the death-associated protein kinase (DAPK) promoter methylation and its clinical relevance in cervical cancer. The DAPK promoter methylation was detected by methylation-specific PCR (MSP) and correlated with DAPK mRNA and protein expression. The effect of DAPK expression on the radiosensitivity of the cervical cancer cell line was assessed by overexpressing DAPK in the radioresistant cell line SiHa. DAPK hypermethylation was found in 56.08% of the cervical cancer samples and was associated with the tumor histological cell type of squamous cell carcinoma (p=0.002) and advanced tumor stage (p=0.005). Subsequently, DAPK protein expression was found to significantly decrease in cervical cancer samples when compared to normal tissues. The DAPK mRNA and protein expression levels were absent or remarkably reduced in SiHa and HeLa in which the DAPK promoter was hypermethylated. The expression levels of DAPK could be restored after demethylation treatment with 5-aza-2'-deoxycytidine. Overexpressing DAPK in vitro had no significant influence to the survival of the radioresistant SiHa cell after being challenged by irradiation. Our findings suggest that DAPK might not directly be responsible for the cellular radiosensitivity, however, DAPK hypermethylation appeared to be of prognostic significance in the advanced stages of cervical cancer.

Hepatic arteriogram for gestational trophoblastic tumor: is it useful?

The presence of liver metastasis will be staged as IV in the FIGO 1992 Gestational Trophoblastic Tumor (GTT) staging. This study was to determine the role of hepatic arteriogram (HAG) in the management of GTT. It is a retrospective analysis of 309 patients treated from 1981 to 2001. Patients were restaged according to the FIGO 1992 classification with or without taking into account the HAG result. Outcome measures including mortality, drug resistance and recurrence of disease, as well as treatment with and without the HAG result were compared. Eighty-one (26.2 percent) patients had HAG and 11 (3.6 percent) also had ultrasound (USG) features of liver metastasis. Interval between diagnosis and treatment were significantly different between USG and HAG positive groups (Mann-Whitney U test, P < 0.05). Seventeen (5.5 percent) of the 309 patients died of the disease and 7 (41.2 percent) of them had liver metastasis. Three (27.3 percent) of the 11 patients who had USG features of liver metastasis died of the disease; mortality is significantly higher than those without USG features of metastasis (Chi-square test, P < 0.05). Patients classified as medium to high risk with or without taking HAG as a feature of liver metastasis were associated with higher mortality and recurrent rate (Chi-square test, P < 0.05). On the other hand, the chance of drug resistance was higher in the medium to high risk group after reclassifying all HAG positive patients as negative for liver metastasis (Chi-square test, P < 0.05). HAG evidence of liver metastasis did not correlate with patient mortality. HAG was not an appropriate investigation in the management of GTT.

p73 expression is associated with the cellular radiosensitivity in cervical cancer after radiotherapy.

Apoptosis is one of the causes of cell death in cervical cancer following radiotherapy. By studying the gene expression profile with cDNA apoptotic array, the p73 gene was found overexpressed in radiosensitive cervical cancers when compared with radioresistant ones. To investigate the role of the p73 gene in relation to clinical assessment of radiosensitivity in cervical cancer based on the findings of residual tumor cells in cervical biopsies after completion of radiotherapy, we studied the protein expression of p73 in 59 cervical cancers after radiotherapy and 68 normal cervices using immunohistochemistry. The expression of p73 was found to be significantly increased in cancer samples and, more importantly, in those samples sensitive to radiotherapy (P < 0.001). The overexpression of p73 actually predicted a better prognosis in cervical cancer patients (P < 0.001). To investigate the possible involvement of p73 downstream genes, the protein expressions of p21 and Bax were studied. The expression of p21, but not Bax, was found to be positively correlated with the expression of p73 (P = 0.001). Furthermore, the epigenetic regulation of p73 expression via DNA methylation was also investigated in 103 cervical cancers and 124 normals. Hypermethylation of p73 gene was observed in 38.8% of cervical cancers, and it was significantly associated with reduced or absent p73 expression (P < 0.001). Reactivation of p73 expression in two cervical cancer cell lines by demethylation treatment supported the role of methylation in the regulation of p73 expression. Our findings suggested that p73 expression was related to the radiosensitivity of cervical cancer cells and may play an important role in the regulation of cellular radiosensitivity.