Prevalence of Fragile Histidine Triad Expression in Tumors from Saudi Arabia: A Tissue Microarray Analysis

AIM

The fragile histidine triad (FHIT) gene was discovered and proposed as a tumor suppressor gene for most human cancers. It encodes the most active common human chromosomal fragile region, FRA3B. We studied the prevalence of loss of FHIT expression in various tumors and correlated its loss with various clinicopathologic features.

METHODS

To determine whether the absence of FHIT expression correlates with clinical variables such as grade, stage, and survival time, we assessed FHIT expression using immunohistochemistry. More than 1,800 tumors from more than 75 tumor categories were analyzed by immunohistochemistry in a tissue microarray format.

RESULTS

Loss of FHIT expression ranged from 19% in ovarian tumors to 67% in lung cancers. Clinical and pathologic features like grade, stage, tumor size, and lymph node metastasis showed correlation with loss of FHIT expression in some tumors. No difference was seen in the survival patterns and loss of FHIT expression in any of the tumor groups studied.

CONCLUSIONS

Loss of FHIT expression is an ubiquitous event in the multistep, multifactorial carcinogenesis process. FHIT may be altered at different stages in different types of cancers. Most of the tumors with a wider prevalence of loss of FHIT expression as an early event show a correlation with clinicopathologic features. However, in some of the tumors, FHIT expression is lost as a late event and is only seen in a fraction of the tumors.

Cervical intraepithelial neoplasia: prognosis by combined LOH analysis of multiple loci

OBJECTIVE

Cervical intraepithelial neoplasias (CIN) show markedly variable clinical behavior. Clinically, it is important to distinguish CIN lesions with different behaviors and identify those likely to persist and progress. The purpose of this study is to explore whether CIN lesions with different clinical behaviors can be stratified by analysis of loss of heterozygosity (LOH) at multiple loci.

METHODS

One hundred sixty-four cases of CIN (54 CIN1, 59 CIN2 and 51 CIN3) were screened for LOH at 12 microsatellite markers including 10 from 3p14, 3p21-22, 6p21 and 11q23. LOH was correlated with clinical follow-up data and high-risk HPV infection.

RESULTS

In a pilot study of 71 cases of CIN, screening of 12 microsatellite markers identified four (D3S1300, D3S1260, D11S35, and D11S528) at which LOH was significantly associated with disease persistence/progression. These four markers were further investigated in a larger cohort, which brought the total number of cases examined to 164. Combined analysis of LOH at the above four loci permitted the identification of 22-47% of CIN lesions depending on the histological grade, which showed disease persistence/progression. LOH at these loci was significantly associated with HPV16 infection. Bioinformatic analysis identified several candidate genes including the fragile histidine triad gene and progesterone receptor gene that may be the target of deletions.

CONCLUSIONS

LOH at D3S1300, D3S1260, D11S35 and D11S528 was significantly associated with cins that showed persistence/progression, and combined LOH analyses at these loci could be used to identify such cases.

Loss of fragile histidine triad protein expression and its clinicopathological significance in gastric cancer

AIM: To investigate the expression of fragile histidine triad protein, Fhit and the possible relationship between its expression and clinicopathological indices in gastric carcinoma.

METHODS: Fhit protein expression was detected in 76 cases of gastric carcinoma, 58 dysplasia and 10 normal mucosae by immunohistochemical method to analyse its relationship to histological grade, clinical stage, metastatic status and prognosis.

RESULTS: The loss of Fhit protein expression was detected in 48/76 (63.2%) cases of cancer tissue, 36/58 (62.1%)cases of adjacent dysplastic tissue and 0/10 cases of normal gastric mucosa. There was a significant difference in the expression of Fhit protein between cancer or adjacent dysplastic tissue and normal gastric mucosa (P=0.000). It was also showed that loss of Fhit protein expression was found first in 35.7% (10/28) of grade I-II, and in 79.2% (38/48) of grade III (P = 0.000); second in 43.8% (14/32)of stage I-II, whereas in 77.3% (34/44) of stage III-IV (P = 0.004); and last in 36.4% (8/22) of tumors without metastasis but in 74.1% (40/54) of those with metastasis (P = 0.003). The significant difference in the loss of expression of Fhit was found between cancers on different histological grade, clinical stage and metastatic status, respectively. Follow-up data showed that there was a significant difference in median survival time between carcinomas with loss of Fhit (33 mos) and those without (71 mos) (Log rank = 20.78; P = 0.000).

CONCLUSION: Fhit protein is an important tumor suppressor protein. Loss of Fhit protein expression may be associated with carcinogenesis, invasion, metastasis and prognosis in gastric carcinoma.