Clinical Research On C-MYC Oncogene Amplification Of Cervical Exfoliated Cells Detected By Fluorescence In Situ Hybridization

Cervical cancer (CC) is the one of malignant tumors which threats to women’s heath seriously in the word wild and the morbidity of CC is ranking the second place in female reproductive system malignant tumors. There are about470000new cases of CC in the word every year and100000new cases in our country. CC mortality rate to4.3/100000in china each year, it’s up to36.0/100000in high-risk areas Shanxi province, besides it has more often founded in young women. It has been proved that high risk human papillomavirus is a essential condition of cervical cancer, companied by other factors it generates cervical intraepithelial neoplasia, carcinoma in situ, early invasive cancer and invasive cervical carcinoma. Epidemiological studies show that it’s close to100%with early treatment to CC, but it is only20%-50%in terminal cervical cancer patients. Therefore it is important to screening and early diagnosing in CIN and cervical cancer.Now, examination of cervical exfoliated cells and detection of HPV are using for cervical cancer screening. A lot of research found that specificity of traditional pap cytology test is as high as90%, but the sensibility is perhaps55%to80%because of the insufficient cervical exfoliated cells, uneven smearing, cell loss, too much blood and bias of doctors. Although the invention of Thin Prep cytology test has changed the methods of smearing in the1990s, whether specificity or sensibility of discovering high level lesions were not improved significantly. Comparing with the cytology test, HPV test has more sensibility in discovering high level lesions and the sensibility is up to95%, but the specificity is about70%. Most HPV infection patient would return to normal in1year, it means that there would be other mechanism in the development and progression of CC. As a result, it is need to find other more reliable indicators to help cytology and HPV test in cervical cancer screening and make it more Accurate, more reliable and more predictive.In recent years, molecular genetics plays a key role in finding the effective way to preventing, early diagnosing and treating cervical cancer and CIN. Some research found that changes in genetic or protein level of oncogene might damage the mechanism of cells growth regulation and develop tumor. C-MYC gene is proved to be a cellular oncogene which is highly correlated with tumor. It locates in8q24area and has always been found amplification and over expression in CC and CIN. Over expression of C-MYC gene reveals that it may develop CIN or even cervical cancer. Sokolova has discovered that there is over expression of C-MYC gene in CC and CIN using fluorescent probes to detect aneusomy in genomic regions which proved that it related with the progression of cervical and CIN. Consequently, testing the over expression of C-MYC gene will help to screen and early diagnose cervical cancer. The standard way to test the gene is fluorescent in situ hybridization (FISH). The method has high specificity and sensibility and is easy to locate and quantify, besides it has better stability and non-invasive to the body. Testing the over expression of C-MYC gene with the use of FISH technique will make up for the Limitations in the current way of diagnosis in CC and CIN, expecting to become an important examination in screening and early diagnosis of cervical lesions.Purpose:In the present study, we detected C-MYC gene amplification of cervical exfoliated epithelial cells by FISH, comparing these results with cytology, HPV test results and histopathology results. Our purpose was to assess the clinical significance of FISH detection of C-MYC gene amplification in cervical cancer sereening and CIN progression prediction.Methods:A total of140patients with informed consent were recruited from the Second Hospital affiliated to Shanxi Medical University. All of them were the inpatients or outpatients of the hospital from September2011to March2012. Each of them was subject to Thin Prep cytology testing, HPV DNA testing, FISH analysis with the C-MYC specific probe and histopathological examination by under c colposcopy-directed. According to cytological diagnosis, we divide the140specimens into5groups including Norm/Infla, ASCUS, LSIL, HSIL and SCC. According to histopathological diagnosis, we divide the140specimens into the other5groups including normal, CIN I, CIN II, CIN III and cervical cancer..All status was measured by chi-square test, and using the sensibility, specificity, false negative proportion, false positive proportion, positive likelihood ratio, negative likelihood ratio and kappa coefficient to access the value of3methods in diagnosing cervical lesions.Results:1. According to cytology test, the C-MYC probe was positive in0.0%,20.9%,45.0%,64.5%,93.8%of Norm/Infla, ASCUS, LSIL, HSIL and SCC cases, respectively.(P=0.000)2. According to histopathological test, the C-MYC probe was positive in2.6%,11.5%,44.4%,71.0%,83.3%of normal, CIN I, CIN II, CIN III and cervical cancer cases, respectively.(P=0.000)3. The more Serious the cervical lesions was, the more number of C-MYC probe positive cells appeared and the more complex karyotype was. Number of C-MYC probe positive cells is0to5and abnormal karyotype was3in normal cases. Number of C-MYC probe positive cells is0to7and abnormal karyotype was3to4in CIN I cases. Number of C-MYC probe positive cells is2to32and abnormal karyotype was3to8in high level cervical lesion cases.4. The sensibility, specificity, false negative proportion, false positive proportion, positive likelihood ratio, negative likelihood ratio of3methods are72.3%,81.3%,27.7%,18.7%,3.87,0.34in cytology test respectively;92.1%,57.8%,7.9%,42.2%,2.18,0.14in HPV test respectively and64.5%、93.8%、35.5%、6.2%、10.4、0.38in C-MYC gene test by FISH respectively. The different in sensibility and specificity among3methods has statistical significance.(P=0.000)5. To access the conformance among3methods with kappa coefficient reveal that the kappa coefficients are0.538and0.399, respectively. It prompts that there are conformance among3methods, but conformance is not high.Conclusions:1. The amplification of C-MYC gene is increased significantly with the higher level cervical lesion. The number of C-MYC probe positive cells in high level cervical lesion is more than it in low level cervical lesion. The amplification of C-MYC gene is related with the development of cervical cancer.2. The more Serious the cervical lesions was, the more number of C-MYC probe positive cells appeared and the more complex karyotype was. C-MYC oncogene may become a new molecular marker using for early diagnosis of CC and CIN.3. Detection of C-MYC gene by using of FISH has a high specificity. It can reduce the false negative proportion and reduce the false positive proportion in a way to guiding the distributary and treatment of CIN. Testing C-MYC oncogene by FISH will become an important assistant way to screening and early diagnosis of cervical lesions.