| Lung cancer is a major cause of human death, and its incidence is increasing recently. Roentgenographic examinations, such as helical computed tomography and magnetic resonance imaging, have been under use widely, and the population-based screening tests for lung cancer using sputum cytology and chest X-ray examination are now widely used in clinics. However, the overall 5-year survival rate of lung cancer is still low after diagnosis, comparing with that of stage I patients (80%). Therefore, to extend patients surviving periods, early diagnosis of lung cancer is urgently needed. Conventional cytological diagnosis of sputum is unsufficient. What the oncologist faced is to explore a practical, reliable and valuable diagnostic method for earlier period of lung cancer. With the developing of biological technology, particularly, people have investigated few specimen or deciduous cells by the polymerase chain reaction method. For instance, people have detected the specific markers of lung cancer in the specimen of sputum or bronchial lavage, hoping early diagnosis. Because lung cancer is originated from bronchial mucous epithelia, some malignant cells from tumor surface can be released from lung carcinoma in situ to late cancer and the released malignant cells can be ejected with mucous secretion by cilia action. Thus, it could be the most convenient way to diagnose lung cancer by examination of deciduous epithelial cells. Heterogeneous nuclear ribonucleoproteins are a group of RNA-binding proteins, the most abundant of which are denoted the A and B subtypes. A few reports have demostrated a link between hnRNPA2/B1 and lung cancer. This study was designed as following: total RNA was isolated from lung cancer cells and the RT-PCR was performed to detect the interested sequence, It was then cloned into pUCm-T plasmids and further sequenced. We detected the expression of hnRNPA2/B1 in constitution of lung with monoclonal antibody and specific cDNA probe by immunohistochemistry and in situ hybridization. Further, We detected the expression of hnRNPA2/B1 in deciduous cells in sputum from a group of clinical lung cancer-suspected patients by immunocytochemistry. Thereby we clarify its sensibitity and specificity in order to evaluate the value for diagnosing lung cancer. We found that:1. Total RNA was isolated successfully from A549 cells and RT-PCR was performed as reports by others. HnRNP A2/B1 cDNA probe was produced after being identified by cDNA sequencing.2. The positive ratio of hnRNP A2/B1 is 85.4%(35/41) in patients with lung cancer, and it is significantly higher than those carcinoma-free patients (30.8%)(P<0.01). HnRNP A2/B1 was localized in the cytoplasm and/or nucleus, but it was presented predominantly in the cytoplasm.3. Four subtypes of lung cancer all showed positive staining of hnRNP A2/B1 protein. The positive ratio of hnRNP A2/B1 is 86.9%(20/23) in patients with squamous cell carcinoma, and it is higher than those adenocarcinomous patients (78.6%), but there is no significant difference (P>0.05).4. The positive ratio of hnRNP A2/B1 is 88.9%(24/27)in patients stage â…¢-â…£, and it is higher than those patients stage â… -â…¡(76.9%), but there is no significant difference (P>0.05).5. The positive ratio of hnRNP A2/B1 is 80.0%(32/40) in smoking patients, and it is significantly higher than those non-smoking patients(50.0%)(P<0.01). 6. The positive ratio of hnRNP A2/B1 mRNA is consistent with that of hnRNP A2/B1 protein and its staining signal is not as stong as immunostaining signal.7. The sensibitity and specificity of hnRNP A2/B1 expression in deciduous cells of sputum is 80.8%(21/26) and 78.9%(15/19). It can be a potential method for finding some patients before clinical diagnosis. We concluded that:1. HnRNP A2/B1 is not correlated with histological types of lung cancer and clinical staging, but it is correlated closely with patients smoking history.2. The sensibitity and specificity of hnRNP A2/B1 is high enough to be used in early diagnosis of lung cancer.3. HnRNP A2/B1 is a new...
|
PDF Full Text Request