Genetic Instability Of Nm23H1, KAI1 Gene And Their Relationship With Clinical Pathological Behaviors Of Tumor In Chinese

BackgroundThe malignant tumors have threatened human health and lives severely. One of the most important reasons is that the microinvasion or micrometastasis exists at the time of surgery and can not be controlled. Therefore it is very important to clarify the mechanism of invasion and metastasis, and quite significant to establish some definite molecular marker and target for the therapy.It has been investigated that the expression of anti-oncoprotein becomes low with the occurrence and metastasis of tumor, then the growth and metastasis of tumor cell are out of control. The main reason that the expression of anti-oncoprotein reduces is anti-oncogenes inactivity. To investigate the mechanism of genetic inactivity, scientists did lots of research on many anti-oncogenes such as P53, P16, et al, and found that the genetic instability, the representative of microsatellite instability and loss of heterozygosity, might be one important factor that leads to genetic mutation, the anti-oncogenes function maladjustment, and the tumor occurrence.Microsatellite instability (MSI) and loss of heterozygosity (LOH), the alteration in length and strength of short tandem repeat sequences are important molecular characteristics of many human tumors. Many researches indicated that MSI or LOH ofanti-oncogenes plays an important role in occurrence of sporadic tumor. MSI was first found in tumors of the hereditary non-polyposis colon carcinoma (HNPCC) syndrome, and then it is found in many other kinds of tumors, such as colon cancer, gastric cancer, carcinoma of endometrium, breast cancer, prostatic cancer and pancreatic cancer, et al. Many studies suggested that the occurrence of MSI increase the frequence of mutation, and moreover, it lead to mutation of genes which has great relationship with tumor which may be an important mechanism of tumor occurrence. According to Knudson's two-hit hypothesis of TSG (tumor suppressor gene) inactivation, the common chromosomal region of LOH is a potential site harbouring TSQ thus LOH is regarded as a valuable molecular genetic marker to find TSGnm23Hl gene is an important anti-oncogene which locates at 17th chromosome (17q21). Steeg et al found that the nm23Hl protein/NDPK, the expression product of nm23Hl gene, could suppress tumor metastasis effectively. However, the studies were mostly on the immunochemistry research of the nm23Hl protein expression, the genetic research of nm23Hl gene on tumor metastasis were very few. KAI1 is a new gene found in recent years, which could suppress tumor metastasis either. Dong et al separated it out from prostatic cancer cell line and identified it as an anticancer gene because it could inhibit prostatic cancer cell metastasis but didn't affect its capable of causing tumors. It has been proved that in many tissue of cancer and many other cell line, there exist KAI1 gene's expression on molecular level. But the expression state in gastric carcinoma was rarely reported and of great controversial. The genetic instability of KAI1 gene in gastric cancer was rarely reported. ObjectiveTo investigate MSI and LOH of locus D17S396, D11S1344 and D11S1326, and their effect on the expression of nm23Hl and KAI1, which would reveal the function mechanism of anti-oncogene and provide experimental basis for metastasis mechanism of cancer.Methods(1) The technology of extraction DNA from paraffin-embedded materials. (2) Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and displaying band by ordinary silver stain. (3) Expression of nm23Hl and KAI1 was detected by Envision immunohistochemistry. (4) Leica-Qwin computer imaging techniques. (5) SPSS statistic software analyzed the experimental results. ResultsStudy on genetic instability of nm23Hl gene in Chinese with the epithelial ovarian tumor?The frequency of heredity instability of malignant ovarian tumors was 40%, which is higher than that of borderline ovarian tumors, while there were no heredity instability occurred in benign ovarian tumors and normal ovarian tissue. Among 25 epithelial ovarian carcinomas, the frequency of LOH in lymph node metastasis cases (66.67%) was significantly higher than those without metastasis (10.53%, P<0.05). Moreover, the frequency of LOH was higher in FIGO stage III and IV than in stage I and II(P<0.05).?The positive frequency of nm23Hl protein in the ovarian epithelial carcinoma and borderline tumors were 56.00% and 57.14%, respectively. They were both higher than those of the benign tumors and normal ovarian tissue(P<0.01). In the epithelial ovarian carcinomas, the positive frequency of nm23Hl protein in lymph node metastasis case was significantly lower than those without metastasis. FIGO stage HI and IV also exhibited lower positive frequency of nm23Hl protein compared with stage I and II.(3)In the epithelial ovarian carcinomas, the positive frequency of nm23Hl protein in LOH positive group was 0.00%, which is lower than that of LOH negative group (P<0.01).Expression of KAI1 protein and genetic instability of KAI1 gene in Chinese with gastric cancer?The expression rate of KAI1 protein was 55.4%(31/56).?With the infiltration of tumor, the frequency of KAI1 protein appeared decreasetendency (P<0.0\). Moreover, the frequency in lymph node metastasis cases was(83.9%) significantly higher than those without (20.0%, P<0.01). Stage TNM I +11(82.8%) also exhibited higher frequency of KAI1 protein than stage TNM III+IV(25.9%, P<0.01).?However, none of 56 gastric cancers showed LOH or MSI at locus D11S1344 and D11S1326. Conclusions(I)The occurrence of LOH of nm23Hl gene might be the molecule marker of the deteriorism of ovarian tissue. Both MSI and LOH of nm23Hl gene controlled development of the epithelial ovarian tumor independently in different paths. LOH could inhibit the expression of nm23Hl in local tissue of the epithelial ovarian carcinoma, which endowed it with high aggressive and poor prognosis.?There is rare loss of hererozygosity or microsatellite instability in KAIlgene in gastric carcinoma. The expression of KAI1 protein has great relationship with the infiltration of tumor, the lymph node metastasis and the prognosis of gastric carcinoma.