Relationship between expression of nm23H1 gene and in vivo and in vitro invasive capacity of gastric cancer cells

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.

Multivariate analysis of predicting lymph node metastasis in gastric cancer

AIM: To analyze the factors influencing lymph node metastasis in gastric cancer and to screen the indicators that could predict more exactly the extent of lymph node metastasis before surgery.

METHODS: The mRNA expression of heparanase, MMP-7, VEGF-C, S100A4, hRad17, hTERT, CDH1, KAI1 and nm23H1 genes were examined in 62 gastric cancer tissues by reverse transcription polymerase chain reaction (RT-PCR). In combination with clinicopathological features, univariate and multivariate analyses were carried out in order to screen the factors affecting lymph node metastasis of gastric carcinoma.

RESULTS: All the genes above were expressed more or less in gastric cancer tissues. With regard to the positive rate, S100A4 and hTERT were the highest (both 96.8%) and CDH1 was the lowest (64.5%). Multivariate analysis with binary logistic regression showed that lymphatic invasion and heparanase mRNA expression were independent factors that judged whether there was lymph node metastasis, and the odds ratios [Exp (B)] were 21.137 (95%CI 2.115-211.211) and 9.768 (95%CI 1.582-60.300) respectively. When predicting the extent of the lymph node metastasis (the number of lymph node metastasis of no more than 6 was regarded as the fewer and lighter; no less than 7 as the more and heavier), MMP-7, hTERT and CDH1 genes mRNA expression and Lauren type of carcinoma were the independent factors (P = 0.037, 0.009, 0.021 and 0.012 respectively), Exp (B) was 8.046, 9.159, 0.087 and 10.068 respectively. The area of serosa involvement was also an important factor.

CONCLUSION: Heparanase mRNA expression and lymphatic invasion of gastric cancer tissue correlate with lymph node metastasis positively. The degree of lymph node metastasis is more serious in patients with diffusive histological type, area of serosa involvement more than 20 cm2 and MMP-7, hTERT mRNA overexpression, and CDH1 loss of expression in gastric cancer. Above examinations before surgery are indicated to arrive at an optimum treatment scheme.

Loss of heterozygosity on chromosome 18 in microdissected gastric cancer cells

AIM: To detect loss of heterozygosity (LOH) on chromosome 18 in primary gastric carcinomas.

METHODS: Short insertion deletion polymorphism (SIDP) markers on chromosome 18 were analyzed using high fidelity-whole genome amplification (HF-WGA) and denatured high pressure liquid chromotography (DHPLC) to detect LOH in gastric cancer cells purified by laser capture microdissection (LCM).

RESULTS: LOH in 3 (MID148, MID150 and MID352) of 9 SIDP loci was found. Three of 10 samples of gastric cancer showed LOH at the same SIDP locus (MID150) (30%) and one of them also demonstrated LOH at the other 2 SIDP loci (MID148, MID352). No LOH was detected in 6 of 9 SIDP loci.

CONCLUSION: Detection of LOH in cancer cells can be achieved by the combination of LCM, HF-WGA and the analysis of SIDP marker by DHPLC. This study provides an alternative new way to map tumor suppressor genes on chromosome 18.