EXPRESSION OF FRAGILE HISTIDINE TRIAD AND P53 IN NON-SMALL CELL LUNG CANCER

Objective： To investigate the expression offragile histidine triad （FHIT） and p53 protein in non-small cell lung cancer （NSCLC） and explore the relationship between their expressions and the clinicopathological features. Methods： FHIT protein and p53 protein were detected by immunohistochemistry in 76 cases of NSCLCs and matched normal lung tissues. Results： Fifty-one cases （67.1%） showed negative expression of FHIT （apparent reduction or loss） and thirty-seven cases （48.7%） showed p53 positive expression （overexpression）. The difference was significant （P=0.04）. However, there was no significant difference in FHIT expression between the p53-positive group and the p53-negative group （64.9% versus 69.2%, P=0.686）. The negative rate of FHIT protein expression was higher in squamous cell carcinoma than in adenocarcinoma, in moderately and poorly differentiated carcinoma than in well-differentiated carcinoma, and in cases with smoking history than in cases without smoking history （P〈0.05）. There was no relationship between FHIT expression and clinical stage or lymph node metastasis. The negative FHIT expression was not an independent predictor of overall survival （P=0.338）. Conclusion： The frequency of negative expression of FHIT protein is higher than that of positive expression of p53 in NSCLCs. The negative expression of FHIT is independent of the expression of p53. The change of expression of FHIT may play a role in the smoking related lung tumorigenesis while it may have no relationship with the progress of NSCLC or prognosis of the patients.

Expression of Ki-67, galectin-3, fragile histidine triad, and parafibromin in malignant and benign parathyroid tumors

Background It is widely recognized that the diagnosis of parathyroid carcinoma （PC） is often difficult because of the overlap of characteristics between malignant and benign parathyroid tumors, especially at an early stage. Our study aimed to investigate the differential expression of Ki-67, galectin-3, fragile histidine triad （FHIT） gene, and parafibromin in PC, parathyroid adenoma （PA）, parathyroid hyperplasia （PH）, and normal parathyroid （NP） tissues; then to assess these expression values for use in differential diagnosis of malignant and benign parathyroid tumors. Methods Data of 15 cases with PC, 19 PAs, and 8 PHs were retrospectively analyzed for their clinical characteristics. The expression of Ki-67, galectin-3, FHIT, and parafibromin were detected via immunohistochemistry in the above-mentioned specimens and 6 NPs as control. Results Complete loss of parafibromin expression was seen in 9 of 15 （60%） carcinomas, and all normal parathyroid tissues and parathyroid benign tumors stained positive for parafibromin except for one （4%） adenoma. Galectin-3 staining was positive in 11 of 15 （73%） carcinomas, 5 of 19 （26%） adenomas, 1 of 8 （12%） hyperplasias, and 0 of 6 normal tissues. The Ki-67 proliferative index was high in 4 of 15 （27%） carcinomas, 1 of 19 （5%） adenomas, and none of the hyperplasia or normal tissues. FHIT expression did not differ appreciably among the tumor types. The combination of overexpression of galectin-3 or loss of parafibromin increased sensitivity for PC to 87%, while the specificity of both positive galectin-3 and positive Ki-67 could reach 100%. Conclusions These data suggested that loss of parafibromin and overexpression of galectin-3 and Ki-67 might help to distinguish parathyroid carcinoma from other parathyroid tumors. And the combination of two or three of these markers might produce better sensitivity and/or specificity for the diagnosis of parathyroid carcinoma.

EGFR Mutation and FHIT Methylation: Inverse Relationship in Patients with Lung Adenocarcinoma and Tuberculosis

Objective:To investigate the genetic correlations between epithelial growth factor receptor(EGFR)mutation and FHIT methylation in patients diagnosed with lung adenocarcinoma(AC)and pulmonary tuberculosis(TB).Methods:The presence of EGFR mutations and the methylation status of the FHIT gene in patients presenting with AC and TB were analyzed.The correlation between TB status and the observed genetic and epigenetic variations was also examined.Results:Among the 90 patients included in the study,38 exhibited EGFR mutations(14 among those with TB and 24 among those without TB),while 29 exhibited FHIT myelination(19 among those with TB and 10 among those without TB).Furthermore,the protein expression levels of EGFR and FHIT were significantly higher in patients diagnosed solely with AC compared to those presenting with both AC and TB.A robust inverse correlation was identified between TB status and the frequency of EGFR mutation(P<0.001).Moreover,significant associations were observed between TB status and FHIT methylation(P<0.01).Conclusion:The findings suggest a correlation between TB and the prevalence of EGFR mutation and FHIT methylation in the pathogenesis of AC.

Relationship between Methylation of FHIT and CDH13 Gene Promoter Region and Liver Cancer

In order to demonstrate the relationship between methylation of fragile histidine triad(FHIT)and T-cadherin/H-cadherin(CDH13)genes and liver cancer,the methylation status of FHIT and CDH13 was detected in healthy individuals and in Mongolian and Han patients with liver cancer.The phenol-chloroform method was used to extract genomic DNA.The methylation specific polymerase chain reaction method was applied to detect the methylation status of FHIT and CDH13.The relationship between smoking and alcohol consumption and gene(FHIT and CDH13)methylation was analyzed.There was significant difference in methylation rate of FHIT(72.67%,34.67%)and CDH13(72.0%,28.0%)between liver cancer patients and healthy individuals of Mongolian descent(P<0.05),as well as that of FHIT(68%,30.67%)and CDH13(64%,26%)between liver cancer patients and healthy individuals of Han individuals(P<0.05).There was also a relationship between smoking and drinking and the methylation of FHIT and CDH13(P<0.05).Thus,the methylation of FHIT and CDH13 had a relationship with liver cancer incidence.Smoking and alcohol ingestion may promote the methylation of FHIT and CDH13.

PROAPOPTOTIC FUNCTION OF FHIT GENE

Tumor suppressor gene plays an important role in maintaining the homeostasis between cell loss and growth. Fragile histidine triad （FHIT） gene found recently was studied in a deep going way; it becomes the focus as a result of its role of anti-tumor in human various type of tissue. Due to the high efficiency of FHIT gene benefiting the anti-tumor, it is proposed as a candidate of tumor suppressor gene though there are several opposite opinions.

MSI/LOH and extron expression of the FHIT gene in gastric carcinoma

We detected loss of heterozygosity(LOH)and microsatellite instabilities(MSI),as well as extron expression of the fragile histidine triad(FHIT)gene in gastric carcinoma(GC),in order to evaluate their association with clinicopathological processes in gastric carcinogenesis.LOH and MSI of the FHIT were detected by using PCR at 4 microsatellite loci:D3S 1300,D3S 4103,D3S 1481,D3S 1234 in cancer tissues from 50 patients with primary GC,with normal mucosa acting as matched controls.FHIT transcripts were detected by nested RT-PCR in 30 cases of GC and their products were sequenced.Results show that the average frequencies of LOH and MSI of the FHIT gene in GC were 32.4%and 26.4%,respectively.There was no correlation between LOH and MSI of the FHIT gene in GC and the histological characteristics of gastric carcinoma(Bormann’s or Lauren’s classification).LOH of the FHIT gene in GC was related to depth invasiveness,and its frequency in GC where serosa was penetrated was significantly higher than that in GC without serosa penetration(73.5%vs 37.5%,P<0.05).The frequency of MSI in GC without lymph node metastasis was significantly higher than that in GC with lymph node metastasis(66.7%vs 34.3%,P<0.05).Aberrant transcripts were found in 11/30 GC tissues.Sequencing analysis of the aberrant fragments found a RT-PCR product missing exons 5–7 in one case of GC,and another product missing exons 4–7.Four of 10(40.0%)cases of primary GC showed absent or decreased expression of the FHIT protein as compared to their matched normal tissues.The findings in this study suggest that LOH and MSI of FHIT gene may induce aberrant extron expression,which might play a role in gastric carcinogenesis.

Absence of FHIT expression is associated with apoptosis inhibition in colorectal cancer

The fragile histidine triad(FHIT)gene,a candidate tumor suppressor gene located at 3p14.2,has been shown to be involved in the carcinogenesis of many human tissues,including digestive tract tissues.However,the expression and the role of the FHIT in the initiation and the development of the colorectal cancer(CRC)are poorly understood.We have shown that the FHIT gene exhibits significantly decreased expression in human CRC compared to colorectal adenoma and normal colorectal tissue by tissue microarray(TMA).The positive rate of FHIT gene expression in normal colorectal tissue,adenoma and adenocarcinoma were 93.75%,68.75%and 46.25%,respectively.We show this decreased expression to be significantly correlated with the progression of colorectal carcinoma(P<0.05)as well as with differentiation and lymph node metastasis(P<0.05).We detected two somatic alterations in the FHIT gene in human CRC.The presence of this mutation correlated significantly with decreased FHIT expression in the human CRC.In our present study we tested the hypothesis that the decreased FHIT expression resulted in apoptosis inhibition associated with abnormal expression of apoptosis related proteins.To test this hypothesis we did a series of experiments.In the first test,we assessed apoptosis status using a standard TUNEL(terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling)assay by comparing FHIT-positive CRC vs.FHIT-negative CRC.In the second experiment,the protein expression of the FHIT and other apoptosis related proteins(Bax,Bcl-2 and Survivin)were measured in human CRC by TMA.Our combined results demonstrate the mutation in the FHIT gene significantly reduced FHIT expression in human CRC.Both TUNEL and TMA experiments demonstrated significantly inhibited apoptosis by down-regulation of Bax and the up-regulation of Survivin and Bcl-2.Collectively,these studies identify the mechanism by which an important tumor suppressor gene,FHIT is inactivated specifically in human CRC contributing to our understanding of the mechanism of colorectal carcinogenesis.