Survivin expression in gastric cancer: Association with histomorphological response to neoadjuvant therapy and prognosis.

BACKGROUND AND OBJECTIVES: Neoadjuvant therapy is applied to improve the prognosis associated with advanced gastric cancer. Only patients with a major response seem to have a survival benefit. Predictive markers to allow individualisation of treatment could be helpful. We examined the association of survivin protein expression with histopathologic response to neoadjuvant chemotherapy and prognosis in patients with gastric cancer. METHODS: Forty patients with gastric cancer received neoadjuvant chemotherapy. Afterwards, 38 patients underwent total gastrectomy, while 2 patients received definitive chemotherapy because of tumour progression. Histomorphologic regression was defined as major response when resected specimens contained <10% tumour cells. Intratumoural survivin expression was determined by immunohistochemistry in pre- and post-therapeutic specimens and correlated with clinicopathologic parameters. RESULTS: The pre- and post-therapeutic intratumoural survivin protein expression was not associated with histomorphologic regression. Post-therapeutic survivin expression did not have prognostic impact. A significant association was detected between pre-therapeutic survivin levels and prognosis: patients with a higher survivin protein expression showed a significant survival benefit. In multivariate analysis pre-therapeutic survivin expression was characterised as an independent prognostic marker, besides pN-status and histopathologic regression. CONCLUSIONS: The pre-therapeutic survivin protein expression seems to be an independent prognostic marker in the multimodality treatment of advanced gastric cancer.

GNAS1 T393C polymorphism is associated with histopathological response to neoadjuvant radiochemotherapy in esophageal cancer.

Recent studies have shown an association between the GNAS1 T393C polymorphism and clinical outcome for various solid tumors. In this study, we genotyped 51 patients from an observational trial on cisplatin/5-FU-based neoadjuvant radiochemotherapy of locally advanced esophageal cancer (cT2-4, Nx, M0) and genotyping was correlated with histomorphological tumor regression. The C-allele frequency in esophageal cancer patients was 0.49. Pearson's chi(2)-test showed a significant (P<0.05) association between tumor regression grades and T393C genotypes. Overall, 63% of the patients in the T-allele group (TT+CT) were minor responders with more than 10% residual vital tumor cells in resection specimens, whereas T(-) genotypes (CC) showed a major histopathological response with less than 10% residual vital tumor cells in 80%. The results support the role of the T393C polymorphism as a predictive molecular marker for tumor response to cisplatin/5-FU-based radiochemotherapy in esophageal cancer.

Survivin mRNA in peripheral blood is frequently detected and significantly decreased following resection of gastrointestinal cancers.

BACKGROUND AND OBJECTIVES: We evaluated if mRNA expression of survivin, an inhibitor of apoptosis, can be used to detect circulating tumor cells in peripheral blood of patients with various gastrointestinal cancers and if they decrease following complete surgical resection. METHODS: Blood samples from 40 gastrointestinal cancer patients were analyzed prior and following surgical resection by direct quantitative real-time reverse transcriptase-PCR (RT-PCR) assays. RESULTS: Survivin mRNA expression was pre-operatively detected in 35 of 40 cancer patients (88%). Post-operative survivin levels were significantly lower than pre-operative levels in 59% of resected patients and were non-detectable in 38% (Wilcoxon rank test: P < 0.04). CONCLUSIONS: This is the first report showing that direct quantitative real-time RT-PCR analysis of survivin mRNA expression in peripheral blood of patients with gastrointestinal cancers is technically feasible. Survivin mRNA levels fall significantly following complete resection and might become a molecular marker for the completeness of surgical resection.

Quantitative c-erbB-2 but not c-erbB-1 mRNA expression is a promising marker to predict minor histopathologic response to neoadjuvant radiochemotherapy in oesophageal cancer.

We examined the potential of quantitative epidermal growth factor receptor (EGFR, synonym: c-erbB-1) and c-erbB-2 (synonym: HER2/neu) mRNA expression to predict minor or major histopathologic response to neoadjuvant radiochemotherapy (cis-platinum, 5-FU, 36 Gy), followed by radical surgical resection, in patients with oesophageal cancer. Tissue samples were collected by endoscopic biopsy prior to treatment. RNA was isolated from biopsies and quantitative real-time reverse transcriptase-polymerase chain reaction assays were performed to determine c-erbB-1 and c-erbB-2 mRNA expression. Relative expression (tumour/paired normal tissue ratio standardised for beta-actin) was calculated for EGFR and c-erbB-2 mRNA. Expression levels were correlated with the objective histopathologic response in resected specimens. Histomorphologic regression was defined as major response when resected specimens contained less than 10% of residual vital tumour cells, or in case a pathologically complete response was achieved. Expression of c-erbB-1 mRNA was not associated with the degree of histomorphological response. In contrast, the relative expression levels of c-erbB-2 mRNA >1 were not associated with major histopathologic responses (sensitivity 41.6%, specificity 100%), and 10 out of 36 (28%) patients could be unequivocally identified, whose tumours did not respond well to the delivered neoadjuvant radiochemotherapy (P<0.01). Quantitative expression levels of c-erbB-2, but not c-erbB-1 mRNA, in pretreatment biopsies appear to predict minor histopathologic response to our neoadjuvant radiochemotherapy protocol. This test could be used to prevent expensive, non effective and potentially harmful therapies in approximately one-fourth of our patients, and leads to a more individualised type of combined modality treatment.

Molecular biology of esophageal cancer.

Squamous cell carcinoma (ESCC) is the most frequent histological subtype in esophageal cancer, although the incidence of esophageal adenocarcinoma (EAC) is increasing faster than any other malignancy in the western world. New developments in the understanding of molecular mechanisms in esophageal cancer comprise analysis of the genetic tumor profiles by CGH (comparative genomic hybridization), the detection of tumor suppressor gene inactivation, and the analysis of proto-oncogenes. Especially the inactivation of the p53 gene proved to be of particular importance for the development of esophageal cancer. Also p15 and p16 have been identified to be involved in the pathogenesis of esophageal cancer by influencing the cyclin kinase inhibitor cascade and DNA mismatch repair processes. Amplification of cyclin D1 results in growth advantage for tumor cells and enhances tumorigenesis; gene amplification and overexpression of cyclin D1 were frequently demonstrated especially in ESCC. Regarding the dysplasia-metaplasia-carcinoma sequence of Barrett's esophagus, inhibition of apoptosis by overexpression of bcl-2 proteins occurs as an early event.

Structure and function of a periplasmic nitrate reductase in Alcaligenes eutrophus H16.

Alcaligenes eutrophus H16 shows three distinct nitrate reductase activities (U. Warnecke-Eberz and B. Friedrich, Arch. Microbiol. 159:405-409, 1993). The periplasmic enzyme, designated NAP (nitrate reductase, periplasmic), has been isolated. The 80-fold-purified heterodimeric enzyme catalyzed nitrate reduction with reduced viologen dyes as electron donors. The nap genes were identified in a library of A. eutrophus H16 megaplasmid DNA by using oligonucleotide probes based on the amino-terminal polypeptide sequences of the two NAP subunits. The two structural genes, designated napA and napB, code for polypeptides of 93 and 18.9 kDa, respectively. Sequence comparisons indicate that the putative gene products are translated with signal peptides of 28 and 35 amino acids, respectively. This is compatible with the fact that NAP activity was found in the soluble fraction of cell extracts and suggests that the mature enzyme is located in the periplasm. The deduced sequence of the large subunit, NAPA, contained two conserved amino-terminal stretches of amino acids found in molybdenum-dependent proteins such as nitrate reductases and formate dehydrogenases, suggesting that NAPA contains the catalytic site. The predicted sequence of the small subunit, NAPB, revealed two potential heme c-binding sites, indicating its involvement in the transfer of electrons. An insertion in the napA gene led to a complete loss of NAP activity but did not abolish the ability of A. eutrophus to use nitrate as a nitrogen source or as an electron acceptor in anaerobic respiration. Nevertheless, the NAP-deficient mutant showed delayed growth after transition from aerobic to anaerobic respiration, suggesting a role for NAP in the adaptation to anaerobic metabolism.