Restriction fragment length polymorphism of the L-myc gene is not a prognostic factor in bladder cancer patients

Meta-Analysis Suggests Association of L-myc EcoRI Polymorphism with Cancer Prognosis

The L-myc EcoRI polymorphism is a noncoding variation in the second intron of the L-myc gene, resulting in S and L alleles. Individuals carrying the S allele tend to have poor prognosis and increased risk of several tumor types, although controversial results have been reported. A meta-analysis of 36 studies on L-myc EcoRI genotyping, including 3563 patients with different types of cancer and 2953 controls, was performed. In lung cancer patients the S/S genotype was significantly associated with lymph node metastasis [odds ratio (OR), 2.8; 95% confidence interval (CI), 1.8-4.3], distant metastasis (OR, 4.7; 95% CI, 2.4-9.2), and stage (OR, 2.3; 95% CI, 1.2-4.4). No association was observed between the S/S genotype and cancer (OR, 1.1; 95% CI, 0.8-1.4). In patients with other cancers, the S/S genotype was significantly associated with tumor recurrence (OR, 2.8; 95% CI, 1.4-6.0), whereas no significant association was seen for the other prognostic parameters. When all types of cancer were examined together, the S/S genotype was associated with lymph node metastasis (OR, 2.3; 95% CI, 1.6-3.3), distant metastasis (OR, 2.9; 95% CI, 1.8-4.6), clinical stage (OR, 1.8; 95% CI, 1.2-2.9), and cancer risk (OR, 1.25; 95% CI, 1.07-1.45). The meta-analysis suggests that the L-myc EcoRI polymorphism is a marker of tumor prognosis in lung cancer and possibly in other types of cancer.

Molecular biology of transitional cell carcinoma

Transitional cell carcinoma (TCC) is the fifth most common solid malignancy in the USA. Radical cystectomy will cure a substantial fraction of patients with minimally invasive TCC, but approximately 50% of patients with muscle-invasive or extravesical disease treated by radical cystectomy alone die of metastatic TCC. Transitional cell carcinoma have a diverse collection of biologic and functional characteristics. This is reflected in a differing clinical course. The limited value of established prognosticators, make the analysis of new molecular parameters of interest in predicting the prognosis of bladder cancer patients; in particular, high-risk patient groups that are at risk of progression and recurrence. Over the past decade, there had been major progress in the elucidation of the molecular genetic changes leading to the development of TCC. This review will highlight these important advances and emphasize the ways in which molecular biology is likely to affect the development of future therapies.

Current understanding of the biology of advanced bladder cancer

Transitional cell carcinoma (TCC) is reported to be the fifth most common solid malignancy in the U.S. Although radical cystectomy will cure a substantial number of patients with minimally invasive TCC, many patients with deeply muscle-invasive or extravesical disease who are treated with radical cystectomy alone die of metastatic TCC, as do patients with metastatic disease. The differing clinical course and the limited value of established prognosticators make analysis of new molecular parameters of interest in predicting the prognosis of patients with bladder cancer, particularly those in high-risk groups who are at risk of disease progression and recurrence. In the current review, a comprehensive MEDLINE/PubMed search of articles pertaining to the biology of TCC from 1965 to the present was performed, as well as a bibliographic review of cross references. TCC follow the general concept of multistep carcinogenesis and proceed through two distinct genetic pathways responsible for generating different TCC morphologies, namely the inactivation of cyclin-dependent kinase inhibitors in low-grade TCC and early p53-mediated abnormalities in high-grade TCC. TCC progression correlates with genetic instability and the accumulation of collaborative genetic lesions mainly involving p53, retinoblastoma, and growth factors. The bulk of these data are derived from cases of localized/locally advanced disease and none are ready yet for routine clinical application; however, the current knowledge has led to the clinical testing of novel biologic observations in several important trials. Understanding of the molecular biology of advanced bladder cancer continues to improve. It is likely that in the new millennium, real breakthroughs in the identification and therapy of high-risk, poor-prognosis patients will come from an integration of molecular modalities in the clinical application.

Association of L-myc polymorphism with lung cancer susceptibility and prognosis in relation to age-selected controls and stratified cases

The association of L-myc polymorphism with cancer susceptibility and prognosis has produced conflicting results. This may have been due to racial/ethnic differences and methodological variations in the studies, such as, control selection and case stratification. Therefore, we investigated the genotype distribution of the L-myc polymorphism in 169 lung cancer patients and 169 non-cancer controls, and analyzed the association of this polymorphism with cancer susceptibility and prognosis in relation to age-specific controls as well as stratified cases. The genotype frequencies in the Taiwanese non-cancer controls were 0.56 (L) and 0.44 (S). Chi-square (chi(2)) analysis indicated a significant difference in the Taiwanese genotype distribution of L-myc compared with that of African-Americans (P=0.001). Logistic regression analysis of cases/controls, adjusted for both age and sex, indicated that an increased frequency of the LL genotype was observed in early-staged patients compared with the non-cancer controls (OR=0.43, 95% CI, 0.20-0.94, P=0.03). In addition, the frequency of the LL genotype was significantly higher in stages I+II patients (47.4%) than in stages III+IV patients (28.4%) (P=0.05). Furthermore, the S allele frequency was significantly increased in stages III+IV patients (P=0.005). As both L-myc and p53 polymorphisms were analyzed for their prognostic value, the patients with an S allele of the L-myc gene and a Pro/Pro variant genotype of the p53 gene had significantly poorer prognoses compared with other patients (P=0.004, by the log rank test). These data suggest that the S allele of the L-myc polymorphism may be associated with lung cancer progression.

Is there any correlation between restriction fragment length polymorphism of the L-MYC gene and metastasis of human nonsmall cell lung cancer?

A potential molecular marker associated with cancer susceptibility as well as metastasis, prognosis and adverse survival, is the L-myc gene. The studies of lung cancer patients from different populations have yielded controversial results. We studied 64 nonsmall cell lung cancer (NSCLC) patients and 37 healthy controls of Turkish origin for L-myc gene polymorphism. Our aim was to test the hypothesis that there was association between L-myc S allele in NSCLC and predisposition to the disease and TNM stage indicating tumor size, node classification and metastasis. Polymerase chain reaction restriction fragment length polymorphism and agarose gel electrophoresis were used to determine the L-myc oncogene genotypes. We found no significant difference, both in the distribution of the LL, LS and SS genotypes and in the allelic frequencies, between the patient group and the control group; that is, the frequencies of L-myc alleles were, L and S, 0.59 and 0.41, 0.60 and 0.40, respectively. Our data between the patient group and the control group; that is, the frequencies of L-myc alleles were, L and S, 0.59 and 0.41, 0.60 and 0.40, respectively. Our data concerning age, sex, size of tumors, histological type of tumors showed no significant association with L-myc genotype. However, a higher frequency of L-myc S allele in the squamous cell carcinoma compared to other histological groups was found, although this difference was not statistically significant. No association was found between the L-myc RFLP and increased risk of metastasis either to the lymph nodes or to other organs. Our results suggested that L-myc gene polymorphism was not a suitable prognostic marker of metastatic development in Turkish NSCLC patients.

Different susceptibility of each L-myc genotype to esophageal cancer risk factors

To understand the relationship between the L-myc genotypes and esophageal cancer risk, a polymerase chain reaction-based restriction fragment length polymorphism analysis was performed on 91 Japanese patients with esophageal cancer and 241 non-cancer outpatients. No significant difference in the distribution of genotypes was observed between patients and controls; 18.7% LL genotype, 56.0% LS and 25.3% SS among patients, and 24.5%, 55.6% and 19.9%, respectively, among controls. Frequency of the s-allele in patients (0.533) was slightly higher than in controls (0.477), but the difference was not statistically significant. However, the odds ratios (ORs) for smoking or heavy drinking were markedly higher in SS and LS genotypes than in LL genotype; age-sex-adjusted ORs for smoking was 7.57 in the SS genotype, 6.40 in the LS genotype and 1.77 in the LL genotype. Age-sex-adjusted ORs for heavy drinking were 19.78, 18.20 and 7.40, respectively. The age-sex-adjusted ORs for both factors combined were 12.77, 18.45 and 1.44, respectively. These results suggested that the L-myc polymorphism might modify the effects of lifestyle factors on esophageal cancer risk.

Allelotype and loss of heterozygosity around the L-myc gene locus in primary lung cancers

L-myc S-allele was reported to be associated with metastasis of lung cancer, indicating the existence of a putative tumor suppressor gene around the L-myc locus, in linkage disequilibrium. The relationship between the S-allele and inactivation of some tumor suppressor gene should be indicated by allelic loss. Therefore, we examined the association between the L-myc S-allele and loss of heterozygosity at 11 loci around the L-myc locus (1p34.3) in primary lesions or other biological characteristics in lung cancer. No associations between the S-allele and allelic loss around the L-myc locus or other characteristics were found. According to the deletion map, three shortest regions of overlap between D1S230 and D1S76 were identified. While loss of heterozygosity at SRO1, between D1S2797 and MYCL1, showed no relationship with the pathological stage, it was more frequently observed in squamous cell carcinoma than adenocarcinoma (P=0.019), and associated with high telomerase activity (P=0.046), an indicator of cellular immortality. In conclusion, we found three shortest regions of overlap (SROs) from D1S2797 to pter, and a tumor suppressor gene, which might be associated with suppression of lung cancer development but not with L-myc S-allele, may exist in SRO1.

L-myc restriction fragment length polymorphism in Japanese patients with esophageal cancer

L-myc polymorphism is a representative genetic trait related to an individual's susceptibility to several cancers. However, there have been no reports concerning the association between esophageal cancer and L-myc polymorphism. To analyze the distribution of polymorphism in Japanese patients with esophageal cancer, a molecular genotyping method using a polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) was used. Based on an analysis of 65 Japanese patients with esophageal cancer and 107 healthy control subjects, a significant difference was observed in either the distribution of genotypes (P=0.012) or of allele frequencies between the two groups (P=0.004). The relative risk of esophageal cancer for genotypes including the shorter allele was 2.9 compared to the longer allele homozygote. Furthermore, the patients with S-allele had a tendency for poor prognosis among those with three genotypes. A significant difference between the distribution of genotypes and the incidence of lymph node metastasis was found based on the clinicopathological features of the cancers. These results suggest that L-myc polymorphism may be implicated as a genetic trait affecting an individual's susceptibility to esophageal cancer, at least among Japanese patients.