Abstract Objective To explore the fragile histidine triad (FHIT) gene expression in lung cancer tissues and their degree of differentiation, and lung cancer histologic classification p53 expression. The method of using tissue microarray using immunohistochemical techniques, FHIT, p53 protein detects lung tissue specimens were 110 cases of lung cancer and 25 patients with benign lesions. Results ① benign lung tissue the FHIT abnormal expression rate of 16%, and lung cancer tissue FHIT abnormal expression rate was 85.5%. Lung cancer tissue and benign lesions of the lung tissue compared to a very significant with sex (P <0.01); degree of differentiation of the different lung tissue, of FHIT expression differences have a very significantly with sex (P <0.01), and FHIT gene expression and lung tissue differentiation degree of positive 0.05）；②p53阴性表达组和阳性表达组，FHIT的表达差异无统计学意义(P>0.05″>related (P <0.01); histological classification of different lung cancer, the FHIT gene expression difference was not statistically significant (P> 0.05); ② p53 negative expression group and positive expression group FHIT expression was no significant difference (P> 0.05 ); p53 abnormal expression rate was 53.6%, the expression of FHIT abnormal expression rate was 85.4%, the difference was highly significant (P <0.01). p53 abnormal expression of FHIT aberrant expression of common detection rate of 93.6%. Conclusion ① FHIT protein may become more effective molecular markers for early diagnosis of lung cancer, the p53 protein and FHIT protein detection helps to improve the detection rate of lung cancer; ② FHIT protein in affecting lung tumor cell differentiation direction, to provide new ideas for clinical drug development .
Key words】 lung cancer; fragile histidine triad (FHIT) gene; of p53
FHIT gene is a candidate tumor suppressor genes mutate easily carcinogenic factors in the external environment, leading to tumor formation. Therefore, to explore the relationship of the FHIT gene in lung cancer, a possible mechanism for lung cancer research to find a breakthrough point.
FHIT, p53 expression in this study using immunohistochemistry and tissue microarray detected 110 cases of lung cancer and 25 patients with benign lung tissue specimens, in order to explore its relationship with the occurrence of lung cancer development and biological behavior .
1 Materials and methods
Surgical resection of lung cancer specimens collected the Beijing Friendship Hospital, 110 cases, 25 cases of benign lesions in lung tissue. All lung cancer cases before surgery without chemotherapy and radiotherapy treatment, HE pathology 3rd edition 1999, according to the the WHO lung and pleural tissue typing standard review by experienced pathologist, including 40 cases of squamous cell carcinoma, adenocarcinoma, 58 cases 12 cases of other cancers; well-differentiated carcinoma in 53 cases, 31 cases of moderately differentiated carcinoma, poorly differentiated carcinoma 26 cases. All organizations in 10% formalin-fixed, paraffin-embedded tissue microarray, 3: 52 points, 60 points, 26 points, constructed by the Beijing Friendship Hospital Pathology, in which each set of chips as positioning markers are normal kidney tissue, chip diameter of 6mm, the thickness of the sheet to 4μm (figure not shown).
1.2 Main reagents and methods
Rabbit anti-FHIT polyclonal antibody was purchased from Beijing Zhongshan Biotechnology Co., Ltd., U.S. ZYMED company’s products; mouse anti-human p53 monoclonal antibody and SP kit purchased from Fuzhou, the development of new biotechnology companies, are American NEOMARKERS products. Procedure according to kit instructions. Phosphate buffer as negative control instead of primary antibody, antigen retrieval using high pressure repair.
1.3 The results of determination
FHIT protein expression within the cytoplasm and nucleus of the bronchial end of the epithelial cells of normal lung tissue and alveolar type II epithelial cells and lung cancer cells. In addition, part of the surrounding cells of the epithelial tissue, such as the nucleus and cytoplasm of lymphocytes and histiocytes positive expression showed brown particles, as shown in Figure 1. Participation with Hao et al  observed positive intensity and positive rate of FHIT protein. Initially staining intensity scoring 0 points: colorless, pale yellow, brownish yellow, tan 3; the press positive cells percentage scoring: positive cells <5% 0 75%为4分；染色强度与阳性细胞百分比的乘积获取一个分值范围：0～">5% to 25% for 1 minute, and 25% to 50% for 2 points, 50% to 75% 3,> 75% 4; staining intensity and percentage of positive cells multiplied to obtain a score range: 0 ~ 12.9 to 12 is divided into a strongly positive (+ +), and 5 to 8 divided into positive (+), from 0 to 4 is divided into weakly positive (+ / -), did not express (-). The definition of lung cancer FHIT protein immunohistochemical staining strongly positive for normal expression, and the rest as decreased or absent FHIT gene, that abnormal expression.
The p53 protein is localized in the nucleus, showing diffuse or scattered in the brown particles of varying thickness, as shown in Figure 2. No staining or expression percentage of cells required according to the method of Kim et al  <30% is negative, expression cell percentage ≥ 30% positive. Of p53-negative normal expression, positive abnormal expression.
1.4 statistical treatment
All data R × C list of rows by χ2 test and count data analysis, SPSS 11.5 statistical package deal with the criteria of P <0.05 was considered statistically significant.
2.1 FHIT gene protein expression in the lung tissue of lung cancer and benign lesions
2.1.1 lung tissue in the FHIT gene abnormal expression was significantly higher than that in benign lesions in lung tissue (P <0.01), see Table 1. Table 1 lung cancer and benign lung tissue expression of the FHIT gene NOTE: χ2 = 49.390, P <0.01
2.1.2 the lung tissue of various degrees of differentiation, FHIT gene expression differences was significant (P <0.01), and the degree of differentiation of the FHIT gene in lung cancer tissue positive correlation (P <0.01), as shown in Table 2. Table related the 2 lung tissue FHIT gene expression in lung cancer differentiation degree Note: χ2 = 53.764, P <0.01; r = 0.608, P <0.01
0.05），见表3。">2.1.3 histological classification of lung cancer, FHIT expression was no significant difference (P> 0.05), as shown in Table 3. 0.05″>Table 3 FHIT gene in lung cancer histologic classification related note: χ2 = 11.267, P> 0.05
2.2 FHIT gene and p53 gene expression in lung cancer.
0.05)，见表4。">2.2.1 p53-negative expression group with p53 positive expression group FHIT gene expression difference was not statistically significant (P> 0.05), as shown in Table 4.
2.2.2 p53 abnormal expression of FHIT aberrant expression of difference highly significant (P <0.01) the common detection rate of 93.6%, see Table 5. 0.05表5 FHIT、 p53异常表达差异性比较注：χ2=26.290, P<0.01″>Table 4 of FHIT, expression of p53 in lung cancer Note: χ2 = 1.765, P> 0.05 Table 5 FHIT, p53 abnormal expression differences Note: χ 2 = 26.290, P <0.01
FHIT gene is a fragile genes susceptible to external environment factors leading to mutations. The study of FHIT variation anomaly occurs in the organization communicating with the external environment, such as the stomach, colon, cervical and lung . FHIT gene on chromosome occupies about 1Mb size cDNA full-length 1095bp sub consisting of 10 exons coding region 500bp .
More about the study of lung cancer in the FHIT gene variation. Sozzi et al  reported that about 80% of small cell lung cancer and FHIT aberrant transcripts present in 40% of non-small cell lung cancer, there is a heterozygous deletion (LOH) in 90% of lung cancer. In this study, tissue microarray of 110 cases of lung cancer and 25 patients with benign lung tissue the FHIT protein Immunohistochemical detection of lung cancer compared with benign lung tissue, FHIT gene expression difference was significant (P <0.01), and the Sozzi research FHIT gene variation is consistent. The results of this study suggest that the FHIT gene is highly expressed in normal tissue and tumor tissue FHIT gene low expression of the FHIT gene may be involved in the process of the formation of lung cancer.
FHIT gene expression in lung cancer tissue differentiation degree reported inconsistent. The results of this study show, lung cancer tissue differentiation degree of extremely significant with sex (P <0.01) of FHIT in lung cancer expression differences, and the degree of expression of the FHIT gene and lung cancer tissue differentiation is related, of FHIT expression more and more, the lung tissue differentiation degree The higher, suggesting that the malignant transformation of cells with the FHIT loss-of-function relationship. Therefore, the clinical drug research to develop the FHIT protein into the tumor, it may promote tumor phenotype reversed, so as to achieve the purpose of cure tumors.
Tomizawa et al.  studies have shown that different histological types of lung cancer in the FHIT protein percentage decrease. This study showed that the histologic classification of lung cancer at the same time, FHIT gene expression difference was not statistically significant (P> 0.05), inconsistent with Tomizawa study. Therefore, learn about the FHIT gene in lung cancer tissue classification relationship needs further study.
The mutation of the p53 gene in human tumors, the inhibitory effect of a more thorough, and mutant p53 protein is easy by immunohistochemistry. Therefore, the detection of mutant p53 protein has become an important symbol of the clinical diagnosis of cancer. The study found that abnormal expression rate of FHIT in lung cancer tissues was significantly higher than that abnormal expression of p53 rate (P <0.01), and Lee  consistent. Comparative expression of p53-negative group and positive expression group FHIT expression was no significant difference (P> 0.05). Therefore, the research suggests that: of FHIT protein deficient and p53 protein in lung cancer tissue abnormalities not related, FHIT expression is an independent indicator, FHIT inactivation may be biological channels outside independent of p53, which is consistent with the study, at the same time, The study found that abnormal expression of p53 was 53.6%, and abnormalities of FHIT expression was 85.4%, FHIT aberrant expression of a much more common than the abnormal expression of p53. Therefore, in the diagnosis of lung cancer, FHIT protein may be more effective than the p53 protein molecular markers. In addition, p53 abnormal expression of FHIT abnormal expression the common detection rate of 93.6%, indicating that combined gene expression protein detection can improve cancer detection rate.
In summary, the results of this research show that the FHIT protein expression in lung cancer reduced or absent lost, and is closely related to the degree of differentiation and lung cancer, and the of FHIT expression of p53 expression no correlation. Step FHIT protein may be an important tumor suppressor protein, plays an important role in the occurrence of lung cancer and evolution. FHIT protein is easily detected by immunohistochemistry, and therefore may become a new following p53 protein more effective markers for the clinical diagnosis of lung cancer.