Fragile Histidine Triad Gene Expression Research Articles

Epigenetic changes in the promoter of the fragile histidine triad (FHIT) gene in human sebocytes under the influence of in vitro culture

Due to the lack of tumor suppressor function of the fragile histidine triad (FHIT) gene product, sebaceous gland carcinomas can develop. The model of the sebocyte cell line SZ95 was used to identify methylated CpG islands at the 5'-end of the FHIT gene and the decrease of gene expression as well as the increase of double-stranded (ds) DNA breaks were examined. Methylation, immunofluorescence analysis, promotor sequencing and treatment of SZ95 cells with 5‑azacytidine/trichostatinA (TSA). The cultivation was accompanied by an increasing methylation of the CpG islands, adecrease of the FHIT gene expression and an accumulation of ds-DNA breaks. Treatment with 5‑azacytidine/TSA showed adecrease in DNA methylation and are-expression of FHIT transcripts. Epigenetic changes in the cellular genome are caused by in vitro cell culture. Consequently, apositive selection of sebocytes with an epigenetically inactivated FHIT locus occurs.

Folate deficiency and aberrant DNA methylation and expression of FHIT gene were associated with cervical pathogenesis.

Aberrant DNA methylation is a recognized feature in various types of human cancer, and folate has a vital role in the epigenetics of mammalian cells by supplying methyl groups for DNA methylation reactions. Fragile histidine triad (FHIT) is a tumor suppressor gene that is frequently silenced in cervical cancer (CC) and preneoplastic lesions. Promoter hypermethylation was previously observed in CC, and its epigenetic silencing has been observed at mRNA or protein levels. Changes in folate intake to modulate DNA methylation may be a mechanistic link to cancer, but this remains to be elucidated. The aim of the present study was to evaluate the influences of folate on FHIT gene methylation and expression in the progression of cervical cancerization. In the present study, red blood cell (RBC) folate levels, FHIT gene methylation status, and mRNA and protein expression levels were detected in 254 women, including normal cervix (NC, n=80), cervical intraepithelial neoplasm grade 1 (CIN1, n=55; CIN2/3, n=55) and cervical squamous cell carcinoma (SCC, n=64) samples. The methylation status of FHIT gene and its mRNA and protein expression levels were measured in CaSki (HPV16 positive) and C33A (HPV16 negative) CC cells treated with different concentrations of folate. The results indicated that FHIT gene methylation rate increased with the severity of cervix lesions, however, RBC folate levels, FHIT mRNA and protein expression levels were reduced. The proliferation inhibition rate, apoptosis rate, and FHIT protein and mRNA expression levels increased along with rising concentrations of folate, whereas the degree of FHIT gene methylation gradually weakened in CaSki or C33A cell lines. The present findings indicated that folate deficiency, FHIT gene promoter hypermethylation and reduced expression were significantly associated with cervical carcinogenesis. The results indicated that folate was able to enhance apoptosis and inhibit the cervical cell proliferation while regulating FHIT gene methylation and expression. Adequate intake of folate to maintain normal DNA methylation status is an effective way for cervical lesions prevention, and demethylation treatment may offer a new strategy for therapy of CC.

FHIT Gene Expression in Acute Lymphoblastic Leukemia and its Clinical Significance

To investigate the expression of the fragile histidine triad (FHIT) gene in acute lymphoblastic leukemia and its clinical significance. The level of expressed FHIT mRNA in peripheral blood from 50 patients with acute lymphoblastic leukemia (ALL) and in 50 peripheral blood samples from healthy volunteers was measured via RT-PCR. Correlation analyses between FHIT gene expression and clinical characteristics (gender, age, white blood count, immunophenotype of acute lymphoblastic leukemia and percentage of blast cells) of the patients were performed. The FHIT gene was expressed at 2.49±7.37 of ALL patients against 14.4±17.9 in the healthy volunteers. The difference in the expression levels between ALL patients and healthy volunteers was statistically significant. The rate of gene expression did not significantly vary with immunophenotype subtypes. Gene expression was also found to be correlated with increase of total leukocyte and decrease in platelets, but not with age, gender, immunophenotyping or percentage of blast cells. FHIT gene expression is low in acute lymphoblastic leukemia and could be a useful marker to monitor minimal residual disease. This gene is also a candidate target for the immunotherapy of acute lymphoblastic leukemia.

Abstract P2-06-05: Association of promoter methylation status of the FHIT gene and Fhit expression with HER2/neu status in breast cancer

Abstract Purpose: Aberrant DNA methylation has been recognized to contribute to breast carcinogenesis, and promoter hypermethylation of many tumor suppressor genes has been correlated with decreased gene expression. The fragile histidine triad (FHIT) gene is a putative tumor suppressor gene in breast and other cancers, and loss of Fhit expression has been observed in breast cancers. The aim of this study was to evaluate the association between methylation of the FHIT gene and its expression in breast cancer, and to investigate whether methylation and expression of the FHIT gene would correlate with clinicopathological characteristics in relation to human epidermal growth factor receptor 2 (HER2) status. Methods: Pyrosequencing of bisulfite treated DNA was performed to study the methylation status of the FHIT gene in 60 breast cancer samples from Korean women obtained at Daegu Catholic University Hospital. We examined the expression of FHIT using tissue microarrays by immunohistochemical staining. Association between the methylation status of the FHIT gene and its expression was analyzed, and the relationship between the FHIT expression and the clinicopathological characteristics of the patients was evaluated. Results: FHIT methylation was detected in 96.7% and positive expression rate of Fhit was 87.3% of the patients. The mean methylation level of the FHIT gene was associated with intratumoral inflammation. Methylation level of the FHIT gene had no significant differences according to molecular subtypes. Loss of Fhit expression was associated with large tumor size, basal-like subtype and positive expression of EGFR. In HER2-negative breast cancers, loss of Fhit expression was significantly associated with tumor size, estrogen receptor status and Ki-67 proliferation index. There was no significant correlation between methylation of the FHIT gene and its expression in this study. Conslusion: Our study revealed that loss of Fhit expression in breast cancer is associated with poor prognostic features, although there is no significance association between the FHIT gene methylation and Fhit expression. We found that in HER2-negatvie breast cancers, loss of Fhit expression was associated with poor prognostic features. These results support the possibility of potential complementation between HER2 and the Fhit pathway. The clinical significance of our findings needs to be further evaluated in larger cohorts with longer follow-up. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-06-05.

Promoter methylation status of the FHIT gene and Fhit expression: Association with HER2/neu status in breast cancer patients

Aberrant DNA methylation has been recognized to contribute to breast carcinogenesis, and promoter hypermethylation of several tumor suppressor genes has been correlated with decreased gene expression. The fragile histidine triad (FHIT) gene is a putative tumor suppressor gene in breast and other types of cancer, and loss of Fhit expression has been observed in breast cancer. The aim of the present study was to evaluate the association between methylation of the FHIT gene and its expression in breast cancer, and to investigate whether methylation and expression of the FHIT gene correlates with clinicopathological characteristics in relation to human epidermal growth factor receptor 2 (HER2) status. Pyrosequencing of bisulfite-treated DNA was performed to study the methylation status of the FHIT gene in 60 breast cancer samples. We examined the expression of Fhit using tissue microarrays by immunohistochemical staining. FHIT methylation was detected in 96.7% and the positive expression rate of Fhit was 87.3% of the patients. The mean methylation level of the FHIT gene was associated with intratumoral inflammation. Methylation level of the FHIT gene had no significant differences according to molecular subtypes. Loss of Fhit expression was associated with large tumor size, basal-like subtype and positive expression of EGFR. In HER2-negative breast cancer, loss of Fhit expression was significantly associated with tumor size, estrogen receptor status and Ki-67 proliferation index. No significant correlation between methylation of the FHIT gene and its expression was observed in the present study. Our results suggest that loss of Fhit expression in breast cancer is associated with poor prognostic features, and it is also relevant to the results in HER2-negative breast cancer. Further studies with larger sample sizes and longer follow-up are required to clarify the predictive and prognostic value of Fhit expression and the FHIT gene methylation status in breast cancer.

Restoration of Fragile Histidine Triad (FHIT) Expression Inhibits Cell Growth and Induces Apoptosis in Cutaneous T-cell Lymphoma Cell Line

ABSTRACTTo investigate the effects of fragile histidine triad (FHIT) restoration on cell proliferation and apoptosis in human cutaneous T-cell lymphoma cell line, Hut-78, in vitro and in nude mouse. Wild-type FHIT gene was transfected by liposome into the Hut-78 cells. The alteration of cell growth curve and soft agar colony formation was studied in vitro and in nude mice. The FHIT gene was stably expressed in Hut-78 cells after the transfection. Compared with the controls, restoration of FHIT expression inhibited cell growth and induced apoptosis. Tumor formation in vivo was strongly suppressed by FHIT gene restoration. Our data demonstrate restoration of FHIT gene expression inhibit the tumor cell growth and provide an option for the treatment.

Helicobacter pylori Infection and Family History of Gastric Cancer Decrease Expression of FHIT Tumor Suppressor Gene in Gastric Mucosa of Dyspeptic Patients

The expression of a fragile histidine triad (FHIT) protein is lost in stomach tumors. The study aimed at determining whether FHIT expression is affected by Helicobacter pylori infection, strain virulence (vacA and cagA genes) and histopathological changes in the gastric mucosa of patients with functional dyspepsia having first-degree relatives with gastric cancer. Eighty-eight never-smoking patients with functional dyspepsia were selected for the study, and 48 of them had first-degree relatives with gastric cancer. Bacterial DNA amplification was used to identify H. pylori colonization. The level of FHIT gene expression was determined by qRT-PCR (mRNA) and Western blot (FHIT protein) analyses. For patients having first-degree relatives with gastric cancer FHIT expression was lower (mRNA by ca. 40-45% and protein by 30%) compared with the control patients (p < .05). H. pylori infection decreased the FHIT mRNA level by 10-35% and the protein level by 10-20%. Bacterial strain vacA(+)cagA(+) lowered FHIT mRNA by ca. 30-35% in the antrum samples of both groups and in corpus samples of patients with first-degree relatives with gastric cancer (p < .05). The FHIT mRNA level was twice as high in control H. pylori-negative patients with intestinal metaplasia, compared with those with non-atrophic gastritis. The decreased FHIT gene expression associated with hereditary factors and with H. pylori infection, especially with vacA(+)cagA(+)-positive strains, may be related to gastric carcinoma development.

Effects of Methylation of FHIT Gene on it's Protein and mRNA Expression in Non-small Cell Lung Cancer.

Fragile histidine triad (FHIT) is a new tumor suppressor gene, whose promoter methylation plays an important role in carcinogenesis. The aim of this study is to explore the effects of CpG island methylation on protein and mRNA expression of FHIT in non-small cell lung cancer, and the roles of FHIT gene in pathogenesis of NSCLC. Methylation and protein expression and transcriptional level of FHIT gene were detected by methylationspecific PCR, Western Blot and RT-PCR in 52 tumor tissues and normal tissues of NSCLC. Methylation in the tumor samples was detected at 38.46%, whereas it occurred at lower frequencies (7.69%) in the corresponding normal lung tissues. Protein expression frequencies was 28.8% in the tumor samples, whereas it was 88.5% in the corresponding normal lung tissues. MRNA expression frequencies was 51.9% in the tumor samples and 100% in the corresponding normal lung tissues. In NSCLC, FHIT gene promoter methylation frequency was significantly increased with decreased expression, suggesting that FHIT promoter methylation plays a role in lung cancer carcinogenesis.

TRAIL‐induced apoptosis of FHIT‐negative lung cancer cells is inhibited by FHIT re‐expression

Fragile histidine triad (FHIT) is a tumor suppressor gene whose allelic loss is associated to a number of human cancers. FHIT protein acts as a diadenosine oligophosphate hydrolase, but its tumor suppressive activity appears as independent from its enzymatic activity. Tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL) can induce apoptosis in the FHIT-negative non-small lung cancer cell line Calu-1. We generated four FHIT-inducible Calu-1 cell clones and demonstrated that FHIT expression was able to protect cells from TRAIL-induced apoptosis, without affecting TRAIL-receptors surface expression. FHIT-specific small interference RNA transfection of SV40-immortalized normal bronchial BEAS cells that show levels of FHIT protein comparable to those of normal bronchial cells, resulted in a significant increase of TRAIL-induced apoptosis. Of note, suramin-mediated inhibition of FHIT enzymatic activity also enhanced TRAIL-induced apoptosis. We conclude that FHIT expression in lung cancer cells is protective from TRAIL-induced apoptosis. Our data suggest that FHIT exerts this protective effect downstream TRAIL-receptors and likely requires its dinucleoside-triphosphate hydrolase activity. As TRAIL represents in the near future a good candidate for death ligands-based anticancer therapy, its potential therapeutic use should be envisaged as preliminary to molecular genetics interventions or drug-induced epigenetic modulations aimed to restoring FHIT gene expression levels in non-small cells lung tumors.

Expression of FHIT gene in cervical carcinoma

Objective To investigate the expression of fragile histidine triad (FHIT) gene in cervical carci-noma and relationship with its clinical-pathological implication. Methods The expression of FHIT was detected by immunohistochemistry SP method in 42 cases of cervical carcinoma and 13 cases of adjacent tissue. Results 47.6% (20 of 42) of cases expressed FttIT in the tumor cells,and 92.3% (12 of 13) of cases of the adjacent tissue were present. There was a significant positive correlation between cervical carcinoma and adjacent tissue(P <0.01). The positive rates of FHIT in high and middle desrees of differentiation were significantly higher than that in low degree of differentiation(54.2% vs 38.9%). Tumors with lymph node metastases(45.9%) had loss FHIT protein expression than those without metastasis(60.0%) (P <0.05). The FHIT expression between Ⅰ and Ⅱ stage,the difference was significant(55.0% vs 45.5%) (P < 0.05). Conclusion FHIT gene plays an improtant role in the occurrence and development of cervical carcinoma. It is suggested that FHIT can be a useful marker for predicting invasion and metas-tasis ability of cervical carcinoma. Key words: Cervical neoplasms; Immunohistochemistry; Fragila histidlne triad

Aberrations of the FHIT Gene and Fhit Protein in Canine Lymphoma Cell Lines

The fragile histidine triad (FHIT) gene is a tumor-associated gene, and aberrant FHIT gene and protein expression have been described in many types of human tumors. Furthermore, it has been reported that FHIT gene inactivation is induced by hypermethylation of 5' CpG islands in the gene or by genomic deletion around the open reading frame (ORF). In this study, we explored the aberrations in the canine FHIT gene and Fhit protein expression and assessed the methylation status and genomic deletions by using 5 canine lymphoma cell lines. We found that the decrease in the expression of the Fhit protein in canine lymphoma cell lines was similar to that in human tumors. The expression of the wild-type FHIT transcript was reduced in all 5 cell lines. However, we could not confirm the involvement of aberrant methylation events in the 5' CpG islands of the canine FHIT gene. We were able to identify homozygous or heterozygous deletions in the canine FHIT genes in all 5 cell lines. Moreover, a widespread genomic deletion of the FHIT gene, which included the ORF region, was detected in 1 cell line. In the present study, we detected aberrations in the FHIT gene and Fhit protein expression in all 5 canine lymphoma cell lines, and this phenomenon might be an important factor in promoting canine lymphoma.

Fragile Histidine Triad (FHIT) Gene and Its Association with p53 Protein Expression in the Progression of Gall Bladder Cancer

Objective: Present study deals with LOH and MSI in FHIT gene and p53 expression in GBC, CC, XGC, and normal GB to elucidate the role of FHIT gene in gall bladder cancer. Methods: Five microsatellite markers D3S1217, D3S1300, D3S1313, D3S1600, and D3S2757, were selected. Results: Among GBC cases the frequency of MSI-H and LOH was 17.5% and 27.5%, respectively. Significant difference was found between GBC and normal GB (p =. 02), and GBC and CC groups (p=. 002) when LOH was compared. Conclusions: Our results suggested CC might act as a preinvasive stage in the pathogenesis of GBC.

The Association of p16INK4A and Fragile Histidine Triad Gene Expression and Cervical Lesions

This cross-sectional study was intended to assess the association between immunohistochemical analysis of p16 and fragile histidine triad (FHIT) and the presence of precancerous cervical lesions. Women seen at Pérola Byington Hospital, São Paulo, Brazil, with histologically confirmed cervicitis (n = 31), cervical intraepithelial neoplasia (CIN) 1 (n = 30), CIN 2,3 (n = 30), and cervical cancer (n = 7) had also cervical material collected for liquid-based cytology, human papillomavirus Hybrid Capture 2 (HC2) test, and p16 and FHIT immunohistochemical reactions. p16 and FHIT reactions were scored as the following: <1%, 1% to 5%, >5% to 25%, and >25%. Receiver operating curve analysis was used to select p16 and FHIT score cutoffs for further categorical analyses. All but one of the 37 CIN 2,3/cancer cases had a p16 score of greater than 1% to 5%. Among the 61 cervicitis/CIN 1 cases, 46 (75%) had a p16 score lower than 1% to 5%. In contrast, no association of FHIT expression and severity of cervical lesions could be demonstrated in this data set. Receiver operating curve analyses suggested the score of 1% to 5% for p16 as the cutoff that best discriminates CIN 2,3/cancer from cervicitis/CIN 1. No cutoff for FHIT scores could be suggested with data set. p16, but not FHIT expression, has the potential to be used as complementary diagnostic tool to investigate human papillomavirus-induced cervical lesions, if these results are confirmed in larger studies.

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.

Decreased fragile histidine triad expression in colorectal cancer and its association with apoptosis inhibition

To detect the expression of fragile histidine triad (FHIT) in normal colorectal tissue, colorectal adenoma and colorectal cancer (CRC) tissue, and to analyze its relationship with the clinicopathological features of CRC, and apoptosis-associated proteins (Bcl-2, Bax, survivin) and apoptosis in colorectal cancer. FHIT mRNA analysis was performed by nested reverse transcription-polymerase chain reaction (RT-PCR) assay. Tissue microarray (TMA) was established to detect the expression of FHIT, Bcl-2, Bax and survivin genes in 80 CRC tissue specimens, 16 colorectal adenoma tissue specimens and 16 hemorrhoid (PPH) tissue specimens during the same period of time as the control. Citrate-microwave-SP was used as immunohistochemical method. The relationship between clinicopathological factors, such as differentiation grades and 5-year survival rate was observed. TUNEL assay was used to detect the apoptosis index in 80 CRC tissue specimens. Ten out of 26 (38.5%) CRC tissue specimens expressed aberrant FHIT transcripts, none of the aberrant FHIT transcripts was observed in the matched normal tissue and colorectal adenoma tissue by nested RT-PCR assay. The positive rate of FHIT gene expression in normal colorectal tissue, colorectal adenoma and carcinoma tissue was 93.75%, 68.75% and 46.25%, respectively. Clinicopathological analysis of patients showed that the decreased FHIT gene expression was not associated with age, sex, serum CEA levels, tumor site and size, histological classification. However, the expression of FHIT was correlated with differentiation grades, pathological stages, lymph node metastases and 5-year survival rate after operation. The positive rate of apoptosis-associated proteins (Bax, Bcl-2 and survivin) in CRC tissue was 72.50%, 51.25% and 77.50%, respectively. The expression of these apoptosis-associated proteins in CRC tissue was correlated with the expression of FHIT. The mean apoptosis index in FHIT negative tumors was significantly lower than that in FHIT positive tumors (5.41 +/- 0.23 vs 0.56 +/- 0.10, P < 0.01). The FHIT gene plays an important role in the regulation of apoptosis and decreased FHIT expression plays a key role in the initiation and progression of colorectal carcinoma.

Down-regulation of FHIT inhibits apoptosis of colorectal cancer: Mechanism and clinical implication

Fragile histidine triad (FHIT) gene, a candidate tumor suppressor gene located at 3p14.2, has been shown to be involved in carcinogenesis of many human tissues, including digestive tract tissues. However, the expression and role of FHIT in the initiation and the development of the colorectal cancer (CRC) are poorly understood. In our present study, we have demonstrated 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 of FHIT gene expression in normal colorectal tissue, adenoma and adenocarcinoma were 93.75%, 68.75% and 46.25%, respectively. We showed that decreased FHIT expression was significantly correlated with the progression of colorectal carcinoma (P<0.05) as well as differentiation and lymph node metastasis (P<0.05). Two somatic mutations in the FHIT gene were also detected in human CRC. The presence of these mutations correlated significantly with decreased FHIT expression in the human CRC. In addition, we identified decreased FHIT expression resulting in apoptosis inhibition and decreasing apoptosis associated with abnormal levels of some pro- and anti-apoptotic proteins (Bax, Bcl-2 and Survivin) by TUNEL and TMA. Our results demonstrated that 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 up-regulation of Survivin and Bcl-2. Collectively, these studies identify the mechanism by which an important tumor suppressor gene, FHIT, inactivated specifically in human CRC, and contributes to our understanding of the mechanism of colorectal carcinogenesis.

Aberrant FHIT protein expression in classical Hodgkin’s lymphoma: a potential marker

The fragile histidine triad (FHIT) gene is frequently inactivated in human cancers; however, the FHIT gene remains unexplored in Hodgkin's lymphoma. The aim of this study was to investigate the role of FHIT expression in classical Hodgkin's lymphoma. Classical Hodgkin's lymphomas were analysed for FHIT gene expression by two-step non-biotin immunohistochemical method and Western blotting. Thirty of the 33 (91%) cases of Hodgkin's lymphoma tested were positive for FHIT protein by immuohistochemistry. The expression of FHIT was mainly located in cytoplasm of Reed-Sternberg (HRS) cells. The protein expression was also documented by Western blotting. The non-Hodgkin's lymphomas were negative for FHIT protein. The results indicate that abnormal FHIT expression is noted frequently in classical Hodgkin's lymphoma and the expression can give insight into the pathogenesis of the disease. The protein may serve as a marker to localise HRS cells in classical Hodgkin's lymphoma.

Molecular genetic alterations of FHIT and p53 genes in benign and malignant thyroid gland lesions

Several oncogenes and tumor-suppressor genes are involved either as early or late event in thyroid gland carcinogenesis. Human FHIT (fragile histidine triad) gene is highly conserved gene whose loss of function may be important in the development and/or progression of various types of cancer. We undertook this study to analyze FHIT and p53 gene status in different benignant and malignant thyroid tumors. Status of these genes as well as intensity of apoptosis was analyzed in tumor tissues by molecular genetic methods, immunohistochemistry, and FACS-scan analysis. The majority of the malignant thyroid cancers displayed aberrant expression of FHIT gene, concominant with p53 gene inactivation. This is followed by low rate of apoptosis, which may be important in the development and/or progression of thyroid cancer. We found higher incidence of p53 mutation and aberrant processing of FHIT mRNA in malignant tumors (papillary, follicular, medullary and anaplastic carcinomas) and in those tumors with distant metastasis. The growth of p53 −/ FHIT − follicular carcinoma of human origin was much faster in nude mice than p53 + / FHIT + follicular carcinoma, and mice had shorter survival rate. Our results show a correlation between aberrant FHIT and p53 expression, low rate of apoptosis, and malignancy. Concomitant aberration of FHIT gene and p53 could be responsible for development of highly malignant types of thyroid cancer and may be considered as a prognostic marker for these tumors.

Decreased Fragile Histidine Triad Gene Messenger RNA Expression in Lung Cancer

BackgroundThe fragile histidine triad (FHIT) gene is located at 3p14.2, a region frequently lost in various tumor types. Lack of FHIT expression has been found to occur frequently in multiple tumor types including lung cancer. We have investigated FHIT messenger RNA (mRNA) levels and other clinicopathologic data, including FHIT and p21 expression in lung cancer. Patients and MethodsThe study included 97 lung cancer cases. The FHIT mRNA levels were quantified by quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) using LightCycler®. ResultsThe FHIT/glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA levels were decreased in tumor tissues from lung cancer (13.844 ± 33.047) compared with adjacent nonmalignant lung tissues (195.763 ± 678.469; P < 0.0001). No significant difference in FHIT/GAPDH mRNA levels was found among age, T status, or lymph node metastasis. The FHIT/GAPDH mRNA level was less in squamous cell carcinoma (0.144 ± 0.246), a smoking-related cancer, than in adenocarcinoma (0.72 ± 1.321; P = 0.0355). FHIT/GAPDH mRNA levels were correlated with FHIT protein (P = 0.0139) and p21 protein (P = 0.0484) expression by immunohistochemistry. The prognosis for patients with lung cancer with low FHIT/GAPDH levels (< 0.26; n = 57) was significantly worse than in the patients with high FHIT/GAPDH levels (> 0.26; n = 40; log-rank test, P = 0.0404). ConclusionUsing the LightCycler® RT-PCR assay, decreased FHIT gene expression might occur early and play an important role in lung tumorigenesis and also correlate with the prognosis of lung cancer. However, further studies are needed to confirm the impact of FHIT in the biologic behavior of the tumor.

Loss of Fragile Histidine Triad Gene Expression in Advanced Lung Cancer Is Consequent to Allelic Loss at 3p14 Locus and Promoter Methylation

The fragile histidine triad (FHIT) gene located at the 3p14.2 locus plays an important role in the pathogenesis of lung cancer. The objective of this study was to analyze loss of heterozygosity and FHIT gene methylation status and correlate them to fhit expression. Bronchoscopically obtained lung biopsies from 30 cases of histologically proven carcinoma of the lung in stage III were assessed for the alterations in the FHIT gene. Fhit protein expression was determined by immunohistochemistry, and transcript levels were determined by reverse transcription-PCR. Microsattelite alterations and methylation status of the Fhit gene promoter was determined by PCR. Loss of heterozygosity at the 3p14 locus was observed in all the 30 cases at least by one of the three microsatellite polymorphic markers. The FHIT gene promoter showed complete methylation in 37% cases and partial methylation in 47% cases, and 16% cases showed no promoter methylation. FHIT full-length coding region (exons 5-9) transcripts were present in eight cases (26.6%), and aberrant transcripts were additionally seen in four cases. Loss of FHIT mRNA expression correlated to FHIT promoter methylation but not to loss of heterozygosity at the 3p14 locus. There was a strong correlation between the expression of FHIT at the transcript and protein level. The apoptotic index estimated by the terminal deoxynucleotidyl transferase-mediated nick end labeling assay was significantly correlated to the fhit protein expression. The results of this study indicate that in locally advanced carcinoma of the lung, there is frequent loss of FHIT expression, and methylation of the FHIT gene promoter is an important mechanism of its inactivation.