Efficacy of laser capture microdissection plus RT-PCR technique in analyzing gene expression levels in human gastric cancer and colon cancer

Background

Thymidylate synthase, dihydropyrimidine dehydrogenase, thymidine phosphorylase, and orotate phosphoribosyltransferase gene expressions are reported to be valid predictive markers for 5-fluorouracil sensitivity to gastrointestinal cancer. For more reliable predictability, their expressions in cancer cells and stromal cells in the cancerous tissue (cancerous stroma) have been separately investigated using laser capture microdissection.

Methods

Thymidylate synthase, dihydropyrimidine dehydrogenase, thymidine phosphorylase, and orotate phosphoribosyltransferase mRNA in cancer cells and cancerous stroma from samples of 47 gastric and 43 colon cancers were separately quantified by reverse transcription polymerase chain reaction after laser capture microdissection.

Results

In both gastric and colon cancers, thymidylate synthase and orotate phosphoribosyltransferase mRNA expressions were higher (p < 0.0001, p <0.0001 respectively in gastric cancer and P = 0.0002, p < 0.0001 respectively in colon cancer) and dihydropyrimidine dehydrogenase mRNA expressions were lower in cancer cells than in cancerous stroma (P = 0.0136 in gastric cancer and p < 0.0001 in colon cancer). In contrast, thymidine phosphorylase mRNA was higher in cancer cells than in cancerous stroma in gastric cancer (p < 0.0001) and lower in cancer cells than in cancerous stroma in colon cancer (P = 0.0055).

Conclusion

By using this method, we could estimate gene expressions separately in cancer cells and stromal cells from colon and gastric cancers, in spite of the amount of stromal tissue. Our method is thought to be useful for accurately evaluating intratumoral gene expressions.

High intratumoral dihydropyrimidine dehydrogenase mRNA levels in pancreatic cancer associated with a high rate of response to S-1

PURPOSE

Although the prognosis in patients with pancreatic cancer has been poor, we recently reported unusually high response rate and survival benefit of S-1 treatment in patients with pancreatic cancer. The aim of this study was to reveal genetic background of this unique activity of S-1 against pancreatic cancer. S-1 is a novel oral fluoropyrimidine derivative consisting of Tegafur (FT) and dihydropyrimidine dehydrogenase (DPD) inhibitor (5-chloro-2,4-dihydroxypyridine; CDHP). Accordingly, intratumoral DPD mRNA expression level was measured to reveal whether the level in pancreatic cancer was different from other GI cancer and whether it was relevant to chemosensitivity.

METHODS

Thirty-three recurrent pancreatic cancer patients treated with S-1 were studied. We obtained 15 responders and 13 non-responders according to the change of serum CA19-9. The mRNA was extracted from paraffin-embedded surgical specimens using laser captured microdissection, and relative expression levels of each DPD/beta-actin were measured using a quantitative reverse transcription polymerase chain reaction (RT-PCR) (Taqman) system. Forty-four colorectal cancer patients and 20 gastric cancer patients treated with S-1 were enrolled as control groups. Thymidylate synthase (TS) mRNA expression levels were also measured.

RESULTS

Intratumoral DPD mRNA expression level was significantly higher in pancreatic cancer than that in colorectal cancer (P = 0.0003; median level, 1.38 vs. 0.44) and gastric cancer (P = 0.0061; 1.38 vs. 0.82). No difference in TS mRNA expression levels was observed among cancer types. DPD expression among responded pancreatic cancer was significantly lower than non-responded. (P = 0.012, Mann-Whitney U test).

CONCLUSIONS

Intratumoral DPD mRNA expression level in pancreatic cancer was significantly higher than the other malignancies. This result may elucidate possible reasons for the high effectiveness of S-1 in pancreatic cancer.

Serum lactate dehydrogenase levels and glycolysis significantly correlate with tumor VEGFA and VEGFR expression in metastatic CRC patients

OBJECTIVES

In an attempt to elucidate the relationship between biomarkers of tumor hypoxia, glycolysis and angiogenesis, we tested the hypothesis that intratumoral gene expression of the hypoxia response (hypoxia inducible factor [HIF1 alpha and 2 alpha]), glycolysis (lactate dehydrogenase A [LDHA]), glucose metabolism (glucose transporter-1 [Glut-1]) and genes involved in angiogenesis (i.e., VEGFA, VEGFR1-3, and neuropilin [NRP]1) are upregulated in metastatic colorectal cancer (mCRC) patients with high serum lactate dehydrogenase (LDH).

PATIENTS AND METHODS

78 formalin-fixed, paraffin-embedded (FFPE) tumor samples were collected from 36 patients with mCRC. Tumor gene expression was correlated with serum LDH levels from the same group of patients. FFPE tissues were dissected using laser-captured microdissection and analyzed for gene expression using a quantitative real-time RT-PCR method.

RESULTS

Intratumoral gene expression of VEGFA and VEGFR1 showed a statistically significant correlation with serum LDH levels (p = 0.006, r = 0.45 and p = 0.004, r = 0.50, respectively). Intratumoral expression of LDHA gene showed a significant correlation with Glut-1, VEGF, HIF1 alpha, HIF2 alpha and VEGFR1 (p = 0.007, r = 0.44; p < 0.001, r = 0.57; p = 0.013, r = 0.41; p = 0.044, r = 0.34; p = 0.026, r = 0.40). Serum LDH levels also correlated with microvessel density analyzed by immunohistochemical analysis.

CONCLUSION

The results demonstrated a significant correlation between the intratumoral gene expression of LDHA, HIF1 alpha, HIF2 alpha, Glut-1, NRP1, VEGFA and VEGFR1. Patients with high serum LDH have increased intratumoral gene expression of VEGFA and VEGFR1. The results also support the hypothesis that serum LDH levels may serve as a surrogate marker for activation of the HIF-related genes in the tumor.

Messenger RNA expression of vascular endothelial growth factor and its receptors in primary colorectal cancer and corresponding liver metastasis

BACKGROUND

Antiangiogenic therapies have been developed recently in combination with traditional chemotherapy for patients with metastatic colorectal cancer. The aim of this study was to clarify the association between messenger RNA (mRNA) levels of vascular endothelial growth factor (VEGF) and its receptors (VEGFR) in primary colorectal cancer and those in corresponding liver metastasis.

METHODS

Thirty-one paired formalin-fixed, paraffin-embedded tumor tissues of colorectal cancer and liver metastasis were dissected by laser capture microdissection. After the mRNA was isolated, a quantitative fluorescent dye real-time reverse transcription-polymerase chain reaction system was used for gene expression measurement.

RESULTS

There was a positive correlation between VEGF mRNA levels in primary colorectal cancer and those in matched liver metastasis (P = .0083, r (s) = 0.48). However, there was no association between mRNA levels of VEGFRs in primary tumor and those in liver metastasis. The mRNA levels of VEGF were associated with those of VEGFR-1 (P = .0026, r (s) = 0.39) but not with those of VEGFR-2. The mRNA levels of VEGF were higher than that of either of the VEGFRs (P < .0001).

CONCLUSIONS

We can predict VEGF mRNA levels, but not those of VEGFRs, in liver metastasis by measuring those in primary colorectal cancer. The mRNA expression of VEGFRs may be more dependent on the surrounding environment than that of VEGF. These results should be useful for the formulation of antiangiogenic therapies for metastatic colorectal cancer. Further studies will be necessary to validate these preliminary data.

Prognostic value of the androgen receptor and its coactivators in patients with D1 prostate cancer

BACKGROUND

Prostate cancer treated with androgen ablation eventually becomes resistant. Because the androgen receptor (AR) signaling axis affects disease progression, AR coactivator molecules could provide clinical prognostic value. This study investigates the association between AR coactivator molecules and clinical outcome measures in patients with prostate cancer.

PATIENTS AND METHODS

Expression levels of AR and its coactivators, SRC1, TIF2, and Her2/neu were determined by quantitative RT-PCR in 148 prostatectomy specimens. AR protein expression was determined by immunohistochemistry. The prognostic value of these expression levels on clinical outcomes was examined.

RESULTS

Increased gene and protein AR expression was not correlated with any of the clinical outcome measures. A non-monotonic correlation was observed between SRC1 and overall survival, as well as Her2/neu and time to prostate-specific PSA recurrence.

CONCLUSION

Although no statistically significant relationships were found, the weak association between some clinical outcomes and two AR coactivators may help improve the current predictive nomogram for patients with prostate cancer.

Thymidylate synthase polymorphisms and mRNA expression are independent chemotherapy predictive markers in esophageal adenocarcinoma patients

Thymidylate synthase (TS) is known to have polymorphisms in the 5' and 3' untranslated region (UTR). These polymorphisms have been reported to be associated with high TS expression and chemoresistance to 5-FU. The aim of this study was to examine the prognostic roles of the 5'-UTR and 3'-UTR TS polymorphisms in esophageal adenocarcinoma patients, as well as their relation with TS mRNA expression. Eighty-three patients with esophageal adenocarcinoma were assessed. Thirty-four had received 5-FU containing chemotherapy and 49 were treated with surgery alone. Surgically resected tumor tissues were analyzed for TS genotype and TS mRNA expression using a quantitative real-time RT-PCR method. No survival difference was seen between the patients with 3RG allele (3RG group) and non-3RG group among surgery-alone patients. However, among patients with a history of 5-FU-based chemotherapy, the non-3RG group showed significantly better overall survival compared to the 3RG group (p=0.02). Moreover, whereas chemotherapy produced a significant increase in survival for the non-3RG group patients, those in the 3RG group obtained no survival benefit from chemotherapy. When patients were classified by low or high TS mRNA expression levels, low TS expressers obtained survival benefit from chemotherapy while high TS expressers did not, although there was no difference of median TS mRNA levels between 3RG and non-3RG group. The 3'-UTR polymorphism was not associated with overall survival. These results suggest that the status of the TS 5'-UTR polymorphism and TS mRNA expression are independent predictive markers for survival benefit from 5-FU-based therapy.

An in vivo platform for translational drug development in pancreatic cancer

Effective development of targeted anticancer agents includes the definition of the optimal biological dose and biomarkers of drug activity. Currently available preclinical models are not optimal to this end. We aimed at generating a model for translational drug development using pancreatic cancer as a prototype. Resected pancreatic cancers from 14 patients were xenografted and expanded in successive groups of nude mice to develop cohorts of tumor-bearing mice suitable for drug therapy in simulated early clinical trials. The xenografted tumors maintain their fundamental genotypic features despite serial passages and recapitulate the genetic heterogeneity of pancreatic cancer. The in vivo platform is useful for integrating drug screening with biomarker discovery. Passages of tumors in successive cohorts of mice do not change their susceptibility to anticancer agents and represent a perpetual live bank, facilitating the application of new technologies that will result in the creation of an integrated stable database of tumor-drug response data and biomarkers.

Human equilibrative nucleoside transporter 1 is associated with the chemosensitivity of gemcitabine in human pancreatic adenocarcinoma and biliary tract carcinoma cells

Gemcitabine has been one of the most commonly used agents for pancreatic adenocarcinoma chemotherapy, but the determinants of the sensitivity of and resistance to this agent are not yet fully understood. In this study with pancreatic carcinoma and biliary tract carcinoma cell lines, we examined the gene expression levels of nucleotide transporters and others related to the metabolism of gemcitabine in the light of sensitivity to this agent. Quantitative RT-PCR demonstrated that one of the nucleotide transporter genes; human equilibrative nucleoside transporter 1 (hENT1) was associated with the sensitivity to gemcitabine as represented by IC50, while the other genes for nucleotide transporter and metabolism were not. We conclude that increased hENT1 expression is a most important determinant of gemcitabine sensitivity at least in an in vitro study.

Towards the molecular characterization of disease: comparison of molecular and histological analysis of esophageal epithelia

Reliable quantification of gene expression offers the possibility of more accurate and prognostically relevant characterization of tissues than potentially subjective interpretations of histopathologists. We measured the expression of 18 selected genes and compared them to histological features in a spectrum of esophageal disease to evaluate the feasibility of molecular characterization of normal and pathologic esophageal epithelia. Esophageal tissue biopsies from 82 patients with foregut symptoms were laser capture microdissected, and the expression levels of 18 selected genes were measured by quantitative real-time polymerase chain reaction. Linear discriminant analysis, which uses combinations of genes to distinguish between histological groups, was performed to compare gene expression and the following five histological groups: (1) normal squamous epithelium (n = 35), (2) reflux esophagitis (n = 13), (3) non-dysplastic Barrett's (n = 33), (4) dysplastic Barrett's (n = 16), (5) adenocarcinoma (n = 31). A panel of seven genes had 90-94% predictive power to distinguish non-dysplastic and dysplastic Barrett's esophagus. Clustering analysis revealed structure in gene expression values even in the absence of histology. Expression levels in 17 genes differed significantly across histological groups. Classification based on gene expression agreed with histopathological assessment in the following percentage of cases: normal squamous epithelium = 53%, reflux esophagitis = 31%, non-dysplastic Barrett's = 76%, dysplastic Barrett's = 40%, and adenocarcinoma = 59%. Interestingly, predictive power improved markedly when inflammatory and dysplastic tissues were removed (77-94%). Gene expression classification agrees well with histopathological examination. When differences occur, it is unclear whether this effect is due to intraobserver variability in pathological diagnosis or to a genuine difference between gene expression and histopathology.

DPD is a molecular determinant of capecitabine efficacy in colorectal cancer

Capecitabine is a fluoropyrimidine-based drug that offers physicians a more convenient treatment for advanced colorectal cancer (CRC), with manageable toxicity and antitumor activity comparable to that of continuous-infusion therapies with 5-fluorouracil (5-FU). However, there are no validated and established predictive factors for clinical outcome of capecitabine efficacy in CRC. The gene expressions of the pyrimidine metabolism enzymes dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP) and thymidylate synthase (TS) have previously been shown to be response determinants of fluoropyrimidine-based drugs in various tumors. Therefore, we investigated whether intratumoral mRNA expression levels of these genes are also associated with the clinical outcome of patients with metastatic CRC treated with first-line capecitabine. Thirty-seven patients with metastatic CRC were enrolled in this study and treated with single agent capecitabine. The intratumoral mRNA levels of DPD, TP and TS were assessed from paraffin-embedded tissue samples using laser-capture-microdissection methods and quantitative real-time PCR. There were 20 women and 17 men with a median age of 61 years (range 49-74). The median progression-free survival was 6.7 months (95% CI, 4.8-11.6 months), with a median follow-up of 14.4 months (range 1.3-18.7 months). Complete response was observed in 1 (3%), partial response in 6 (20%), stable disease in 14 (47%) and progressive disease in 9 (30%) patients (response was inevaluable in 7 patients). Higher gene expression levels of DPD were associated with resistance to capecitabine (P=0.032; Kruskal-Wallis test). Patients with a lower mRNA amount of DPD (<or=0.46) had a longer progression-free survival compared with patients that had a higher mRNA amount (8.0 vs. 3.3 months; adjusted P=0.048; log-rank test). This pilot study suggests that intratumoral gene expression levels of DPD may be useful in predicting the clinical outcome of patients with metastatic CRC with first-line single agent capecitabine treatment. Our data should be validated in larger and prospective clinical trials.

Plasma DNA as a molecular marker for completeness of resection and recurrent disease in patients with esophageal cancer

OBJECTIVE

To identify a marker for completeness of resection and recurrent disease in patients with esophageal cancer.

DESIGN

Case series.

SETTING

Department of Surgery of the University of Southern California.

PATIENTS

Forty-four healthy subjects and 45 patients with esophageal cancer prior to esophagectomy. Six patients were unresectable and 39 had a complete resection.

MAIN OUTCOME MEASURES

Plasma DNA levels were measured using polymerase chain reaction. Twenty resected patients had follow-up plasma DNA levels measured.

RESULTS

Preoperatively, plasma DNA levels exceeded the normal level in 38 (84%) of 45 patients. Preoperatively, 12 patients received neoadjuvant therapy and 11 had plasma DNA levels higher than normal. All 6 unresectable patients had DNA levels higher than normal. At initial follow-up, the plasma DNA levels remained higher than normal in 2 (10%) of 20 patients, and systemic disease was subsequently detected in each. Plasma DNA levels dropped lower than or remained normal in 18 (90%) of 20. In 14 of 18 patients, there was no evidence of recurrent disease at a median of 12 months (range, 3-20 months); in 4 patients, the plasma DNA level rose higher than normal on follow-up and all developed subsequent systemic disease on computed tomographic or positron emission tomographic scan. Six of the 20 patients developed systemic disease during the follow-up (2 had persistently elevated plasma DNA levels, and 4 developed elevated plasma DNA levels at subsequent follow-ups). In 4 of these 6 patients, elevated plasma DNA levels were detected prior to imaging evidence of disease.

CONCLUSIONS

Plasma DNA levels are significantly elevated in patients with esophageal cancer and following complete resection should return to normal. Persistently elevated plasma DNA levels after resection or levels that rise on follow-up indicate residual or recurrent disease.

Reduction of interleukin 8 gene expression in reflux esophagitis and Barrett's esophagus with antireflux surgery

HYPOTHESIS

Chronic inflammation of esophageal mucosa secondary to refluxed gastric juice increases gene expression of interleukin 8 (IL-8). Antireflux surgery can reduce this overexpression.

DESIGN

Prospective analysis of archival paraffin-embedded tissue.

SETTING

Academic tertiary medical center.

PATIENTS AND METHODS

One hundred eight patients with reflux symptoms were classified according to pH monitoring and endoscopic and histologic findings. Twenty patients did not have reflux or mucosal injury; 47 had reflux disease (16 esophagitis and 31 Barrett's esophagus), 20 had dysplasia, and 21 had adenocarcinoma. Microdissection was performed to exclude inflammatory cells and stromal tissue. After RNA isolation and reverse transcription, IL-8 messenger RNA expression was measured using quantitative real-time polymerase chain reaction. All patients with reflux disease had Nissen fundoplication with biopsies at matched levels within the esophagus preoperation and postoperation.

RESULTS

Expression of IL-8 was increased in patients with reflux compared with those without reflux. Patients with the highest IL-8 expression were those with Barrett's dysplasia and adenocarcinoma (P<.001). In patients with reflux, Nissen fundoplication led to significantly decreased IL-8 expression compared with preoperative levels in esophagitis (P = .01) and Barrett's esophagus (P = .03).

CONCLUSIONS

Interleukin 8 messenger RNA expression increases during the progression of reflux disease from normal squamous mucosa to esophageal adenocarcinoma. Elimination of reflux with Nissen fundoplication significantly reduces IL-8 expression in both squamous and Barrett's mucosa. These results demonstrate that effective antireflux surgery can modulate the gene expression of esophageal mucosa and may impact the natural history of reflux disease.

Human equilibrative nucleoside transporter 1 is associated with the chemosensitivity of gemcitabine in human pancreatic adenocarcinoma and biliary tract carcinoma cells

Gemcitabine has been one of the most commonly used agents for pancreatic adenocarcinoma chemotherapy, but the determinants of the sensitivity of and resistance to this agent are not yet fully understood. In this study with pancreatic carcinoma and biliary tract carcinoma cell lines, we examined the gene expression levels of nucleotide transporters and others related to the metabolism of gemcitabine in the light of sensitivity to this agent. Quantitative RT-PCR demonstrated that one of the nucleotide transporter genes; human equilibrative nucleoside transporter 1 (hENT1) was associated with the sensitivity to gemcitabine as represented by IC50, while the other genes for nucleotide transporter and metabolism were not. We conclude that increased hENT1 expression is a most important determinant of gemcitabine sensitivity at least in an in vitro study.

Predictive Value of MSH2 Gene Expression in Colorectal Cancer Treated with Capecitabine

PURPOSE

The objective of the present study was to evaluate the gene expression of the DNA mismatch repair gene MSH2 as a predictive marker in advanced colorectal cancer (CRC) treated with first-line capecitabine.

PATIENTS AND METHODS

Microdissection of paraffin-embedded tumor tissue, RNA extraction, and quantitative polymerase chain reaction were performed on tumors obtained from 37 patients with advanced CRC.

RESULTS

The median relative gene expression of MSH2 was 0.65 (quartiles 0.5-0.8) in nonresponders and 1.25 (quartiles 0.92-1.38) for responders (P = 0.038). High expression of MSH2 was associated with a hazard ratio of 0.5 (95% confidence interval, 0.23-1.11; P = 0.083) in survival analysis.

CONCLUSION

The higher gene expression of MSH2 in responders and the trend for predicting overall survival indicates a predictive value of this marker in the treatment of advanced CRC with capecitabine.

Gene expression levels of epidermal growth factor receptor, survivin, and vascular endothelial growth factor as molecular markers of lymph node involvement in patients with locally advanced rectal cancer

BACKGROUND

Patients diagnosed with locally advanced rectal cancer usually receive surgical resection and adjuvant chemoradiation therapy. Lymph node involvement is an important clinical prognostic factor affecting recurrence and survival. Few studies have explored molecular markers associated with lymph node involvement of rectal cancer.

PATIENTS AND METHODS

Tissue was obtained from 59 patients with locally advanced rectal cancer who were treated with adjuvant chemoradiation therapy. We assessed messenger RNA (mRNA) levels of genes involved in pathways of angiogenesis (vascular endothelial growth factor [VEGF], cyclooxygenase-2), apoptosis (survivin), tumor growth and epidermal growth factor receptor (EGFR), DNA repair (ERCC1, Rad51), and the DNA synthesis in tumor tissue and tumor-adjacent normal tissue from paraffin-embedded samples using laser-capture microdissection methods.

RESULTS

Twenty-four patients had no involvement of regional lymph nodes and 35 had lymph node metastases. In univariate analysis, patients with lymph node involvement had higher mRNA levels of VEGF and survivin in tumor tissue and EGFR in tumor-adjacent normal tissue compared with patients with no lymph node involvement (P < 0.1; t test). Multivariate analysis using recursive partitioning showed that mRNA levels of EGFR, survivin, and Rad51 are primarily responsible for delineating node positive from node negative.

CONCLUSION

Gene expression of VEGF, survivin, and EGFR could be associated with lymph node involvement in patients with locally advanced rectal cancer. Further independent studies of those gene expression levels and lymph node involvement are warranted to better characterize the associations.

Molecular factors of 5-fluorouracil metabolism in colorectal cancer: analysis of primary tumor and lymph node metastasis

Thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and thymidine phosphorylase (TP) are predictive markers for tumor response to 5-fluorouracil-based therapies. To determine whether gene expression values measured in primary cancer tissue would be useful for prediction of response of lymph node metastases, the expressions of these genes were quantitatively analyzed in 35 pairs of primary colorectal cancer (CRC) and corresponding lymph node metastases using real-time PCR. DPD and TP mRNA levels were significantly lower in the primary colorectal tumor and lymph node metastases compared with the normal adjacent stroma tissue (p<0.01), whereas TS mRNA levels were significantly higher in the primary tumor and lymph node metastases than in the normal adjacent tissue (p<0.001). Median gene expression levels of TP and TS did not differ significantly between primary colorectal tumor and corresponding lymph node metastasis but median DPD gene expression levels in the lymph node metastases were significantly higher compared to matched primary colorectal tumors (p=0.015). There was a significant correlation for DPD, TP and TS gene expression levels between primary colorectal tumor specimens and the matched lymph node metastasis. These results suggest that biopsies of the tumor of origin may be valid for determining predictive markers for chemotherapy response in patients with metastatic CRC.

ERCC1 and RRM1 gene expressions but not EGFR are predictive of shorter survival in advanced non-small-cell lung cancer treated with cisplatin and gemcitabine

BACKGROUND

Pivotal studies indicate a role of excision repair cross-complementation 1 (ERCC1) gene and ribonucleotide reductase M1 (RRM1) gene in conferring a differential sensitivity to cytotoxic chemotherapy and epidermal growth factor receptor (EGFR) gene has been recently extensively investigated in non-small-cell lung cancer (NSCLC).

DESIGN

Formalin-fixed, paraffin-embedded bronchoscopic/fine needle aspiration biopsies obtained from 70 patients with advanced NSCLC were retrospectively collected to investigate the expression level of ERCC1, RRM1 and EGFR by real-time PCR. Sufficient amounts of messenger RNA (mRNA) were successfully extracted from 61 (87%) specimens, reverse transcribed and amplified with intron-spanning primers. Forty-one patients had stage IV disease and 43 received cisplatin/gemcitabine chemotherapy.

RESULTS

A strong correlation between ERCC1 and RRM1 mRNA levels (r(s) = 0.624, P < 0.0001) was found. Median survival time in patients with low ERCC1 was significantly longer (17.3 versus 10.9, P = 0.0032 log-rank test) as well as in patients with low RRM1 (13.9 versus 10.9, P = 0.0390 log-rank test). Concomitant low expression levels of ERCC1 and RRM1 (n = 33) were predictive of a better outcome (14.9 versus 10.0, P = 0.0345 log-rank test). Among cisplatin-treated patients, a low ERCC1 level was highly predictive of a longer survival (23.0 versus 12.4, P = 0.0001 log-rank test). No correlation between gene expression levels and histology was reported. No significant correlation between EGFR expression level and survival was found. At multivariate analysis, performance status, response to chemotherapy, presence of weight loss and ERCC1 were independent prognostic factors for survival.

CONCLUSIONS

This retrospective study further validates ERCC1 and RRM1 genes as reliable candidates for customized chemotherapy and shows a higher impact on the survival of NSCLC patients treated with cisplatin/gemcitabine for ERCC1. Prospective pharmacogenomic studies represent a research priority in early and advanced NSCLC.

Epidermal growth factor receptor and epidermal growth factor receptor variant III gene expression in metastatic colorectal cancer

PURPOSE

The epidermal growth factor receptor (EGFR) variant type III (variously called EGFRvIII, de2-7 EGFR, or triangle upEGFR) has an in-frame deletion of the extracellular domain and is found in numerous types of human tumors. Because EGFRvIII has been reported to be tumor specific and has oncogenic potential, it is being investigated as a potential therapeutic target, but to our knowledge, there is only 1 previous report about EGFRvIII by immunohistochemistry in colorectal cancer. Our aim was to indicate the frequency of gene expressions of EGFRvIII and EGFR in metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

Forty-five patients with mCRC who received the chemotherapy for metastatic disease were analyzed for the EGFRvIII variant. Paraffin-embedded tumor tissues were dissected using laser-captured microdissection and analyzed for the EGFR and EGFRvIII messenger RNA expression using a quantitative real-time reverse-transcriptase polymerase chain reaction method. Gene expression values (relative messenger RNA levels) are expressed as ratios (differences from the cycle threshold values) between the target gene and internal reference gene (beta-actin). Twenty-five women and 20 men with a median age of 55 years (range, 25-76 years) were included in this study.

RESULTS

We did not find any expression of EGFRvIII in these 45 patients except for control cell lines as U87.EGFRvIII. However, EGFR gene expression was found in 43 of 45 (95.6%) with a range of 0.38-2.83.

CONCLUSION

Our results demonstrate that the expression of EGFRvIII is rare, but most colon cancer demonstrates EGFR gene expression. We conclude that EGFRvIII does not play an important role in mCRC.

Increasing cyclooxygenase-2 (cox-2) gene expression in the progression of Barrett's esophagus to adenocarcinoma correlates with that of Bcl-2

Previous studies from our laboratory and others have suggested that increased expression of cox-2 is important in the genesis of esophageal adenocarcinoma. In vitro studies suggest that cox-2 regulates expression of the anti-apoptotic protein bcl-2, thus possibly accounting for reduced apoptosis in carcinogenesis. The aim of this study was to investigate the relationship of these 2 genes in the development of Barrett's-associated adenocarcinoma. Histologic sections from endoscopic biopsies or esophagectomy specimens were classified as non-dysplastic Barrett's (n = 30), intraepithelial neoplasia (n = 12) and adenocarcinoma (n = 48). The desired tissue was isolated by laser capture microdissection and expression levels of cox-2 and bcl-2 were measured by quantitative real-time PCR (Taqman). Gene expression levels were compared to samples of the distal esophageal squamous epithelium (n = 55) and reflux-esophagitis (n = 25), without Barrett's or cancer. Expression of both bcl-2 and cox-2 were increased in non-dysplastic Barrett's (p = 0.0077, p = 0.0037), intraepithelial neoplasia (p = 0.0053, p = 0.0220) and adenocarcinoma (p < 0.0001, p < 0.0001) compared to squamous epithelium or reflux-esophagitis. Furthermore, there is a significant correlation between these two genes, especially in carcinoma (p < 0.0001).

Genistein-induced neuroendocrine differentiation of prostate cancer cells

BACKGROUND

Neuroendocrine (NE) cells are present in normal prostate and their number appears to be increased in advanced prostate cancer (PCA). In this study, we studied the effect of the phytoestrogen, genistein, on NE differentiation of LNCaP cells in vitro.

METHODS

Neuroendocrine marker expression of LNCaP cells exposed to genistein was measured by immunohistochemistry, Western blot, and real-time PCR methods. Western blot analysis was used to study cell cycle and signaling pathways induced by genistein treatment.

RESULTS

Six days after continuous genistein treatment, the majority of genistein-surviving cancer cells underwent transdifferentiation into a NE-like phenotype overexpressing the NE markers chromogranin A, synaptophysin, serotonin, and beta-III tubulin. This NE differentiation process was associated with upregulation of the cell cycle modulators p21, p27, and p53, and activation of the MAPK and STAT3 pathways.

CONCLUSION

Our data indicate that genistein evokes not only apoptosis but also NE transdifferentiation of PCA cells.

Cdx-2 expression in squamous and metaplastic columnar epithelia of the esophagus

The molecular pathogenesis of Barrett's esophagus is poorly understood. Evidence suggests that at a phenotypic level, the metaplastic process begins with the transformation of squamous epithelium in the distal esophagus to cardiac mucosa, which subsequently becomes intestinalized. The homeobox gene Cdx-2 has been shown to be an important transcriptional regulator of embryonic differentiation and maintenance of adult intestinal type epithelium. We hypothesized that Cdx-2 gene expression levels increase with the phenotypic transformation of normal squamous mucosa to the intestinalized columnar mucosa of Barrett's esophagus. Endoscopic biopsies were obtained at the gastroesophageal junction in patients with symptoms of gastroesophageal reflux disease and classified according to histology: normal squamous mucosa (n = 62), cardiac mucosa (n = 19), oxynto-cardiac mucosa (n = 14), and intestinal metaplasia (n = 15). Duodenal biopsies (n = 26) served as the columnar control. After laser capture microdissection and RNA isolation, gene expression levels of Cdx-2 were measured in each tissue type by quantitative reverse transcription polymerase chain reaction. Consistent with its known function, Cdx-2 gene expression levels were highest in duodenal mucosa and nearly absent in squamous epithelium. There was a stepwise increase in Cdx-2 gene expression from cardiac to Barrett's epithelium (P < 0.001). Expression levels of Cdx-2 in cardiac and oxynto-cardiac mucosa were 40-70 times higher and Barrett's mucosa 400 times higher than that found in squamous epithelium. Relative expression of the homeobox gene Cdx-2, known to induce differentiation of intestinal type epithelium, increases in a stepwise fashion during the phenotypic transformation of distal esophageal squamous mucosa to cardiac columnar mucosa and to the intestinalized columnar mucosa of Barrett's esophagus. Therefore, Cdx-2 may be a potential biomarker to detect the early transition to Barrett's esophagus.

5-fluorouracil-related gene expression levels in primary colorectal cancer and corresponding liver metastasis

Gene expression levels of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP) and orotate phosphoribosyl transferase (OPRT) have been shown to be associated with response to 5-fluorouracil-based therapies. Analyzing these gene expression levels in liver metastases is important to obtain the best prediction of therapy. Our aim was to determine how TS, DPD, TP and OPRT gene expression levels in primary colorectal cancer (CRC) were related to those in liver metastases. Formalin-fixed, paraffin-embedded tumor specimens from 31 pairs of primary CRC and corresponding liver metastases were dissected by using laser-captured microdissection. RNA was extracted and cDNA was prepared by reverse-transcription. Quantitation of target gene and internal reference gene was performed using real-time PCR. No significant difference was seen between median mRNA expression levels of TS, DPD, TP and OPRT in primary cancer and those in corresponding liver metastases (median value: TS 1.48 vs. 1.43; p=0.92, DPD 0.19 vs.0.12; p=0.10, TP 1.20 vs. 0.98; p=0.39, OPRT 1.17 vs. 0.95; p=0.10). When matched tissue sets were compared on an individual basis, there was a significant correlation for TS mRNA expression between primary cancer and corresponding liver metastases (rs=0.52, p=0.0026). However, no correlation was seen between matched sets for DPD, TP or OPRT. Significant correlation was seen between DPD and TP expression levels in both primary CRC (rs=0.38, p=0.03) and liver metastases (rs=0.72, p<0.0001). A good prediction of TS mRNA levels in liver metastases can be obtained by measuring those of primary CRC, although no correlation was seen for DPD, TP and OPRT.

Epidermal growth factor receptor messenger RNA expression, gene dosage, and gefitinib sensitivity in non-small cell lung cancer

PURPOSE

Epidermal growth factor receptor (EGFR) mRNA expression and EGFR gene dosage by quantitative PCR in tumor samples obtained from patients with gefitinib-treated non-small cell lung cancer were analyzed in order to determine the association with treatment outcome, clinical, and biological features [EGFR copy number by fluorescent in situ hybridization (FISH), EGFR tyrosine kinase mutations, and EGFR protein expression].

EXPERIMENTAL DESIGN

EGFR mRNA expression was measured by real-time quantitative reverse transcription-PCR in 64 patients, and EGFR gene dosage was analyzed by real-time quantitative PCR in 82 patients from paraffin-embedded specimens.

RESULTS

EGFR mRNA expression was higher in responders to gefitinib as compared with nonresponders (P = 0.012). Patients with high EGFR mRNA expression (>5.01) had 43% response probability, whereas patients with low EGFR mRNA expression had 8% response probability (P = 0.006). Patients with high EGFR mRNA expression had longer median progression-free (5.3 versus 2.8 months, P = 0.028) but not overall survival (13.8 versus 10.9 months, P = 0.87). EGFR mRNA expression was higher in FISH-positive patients (P = 0.001) and in patients with positive EGFR immunostaining (P < 0.001) but not in patients with EGFR mutations (P = 0.19). EGFR gene dosage did not predict response (P = 0.54), progression-free (P = 0.73), or overall survival (P = 0.89). EGFR gene dosage was not associated with FISH positivity (P = 0.15), relative mRNA expression (P = 0.27), EGFR mutation status (P = 0.39), and EGFR protein expression (P = 0.35).

CONCLUSION

EGFR mRNA expression is a predictive biomarker for response to gefitinib and to progression-free survival after gefitinib treatment. EGFR gene dosage is neither predictive for response nor progression-free nor overall survival.

Antireflux surgery normalizes cyclooxygenase-2 expression in squamous epithelium of the distal esophagus

BACKGROUND

In some patients GERD presents with heartburn and regurgitation symptoms but a relative paucity of endoscopic and clinical findings, while in others symptoms may be minor or absent yet there is significant mucosal damage on endoscopy including the presence of Barrett's esophagus. The initial injury of gastroesophageal reflux is to the squamous esophageal mucosa, but while substantial research has been devoted to determining which genes are involved in the progression of Barrett's to dysplasia and cancer, little is known about the gene expression alterations in the squamous mucosa of patients with reflux. We hypothesized that the expression of cyclooxygenase-2 (Cox-2) might be increased in the squamous esophageal mucosal of patients with reflux, and might be a molecular indicator of reflux injury. Further, we hypothesized that Cox-2 expression in the squamous mucosa would be reduced following the elimination of reflux with an antireflux operation.

METHODS

Biopsies of the distal esophageal squamous mucosa were taken 3 cm above the squamocolumnar junction (SCJ) in 28 GERD patients before and after Nissen fundoplication. Following microdissection and RNA isolation, quantitative real-time PCR was used to measure Cox-2 gene expression in paraffin-embedded (N = 16) and fresh frozen (N = 12) tissue. Biopsies from patients (paraffin N = 15, frozen N = 14) with normal acid exposure and no evidence of mucosal injury were analyzed as controls.

RESULTS

Median Cox-2 expression in the squamous epithelium from paraffin embedded biopsies in patients with reflux disease was significantly increased compared to controls (p = 0.04). The presence of esophagitis or Barrett's esophagus did not significantly alter the expression of Cox-2 compared to patients with nonerosive reflux disease (NERD). After antireflux surgery median Cox-2 expression values were significantly reduced (p = 0.0003) and were normalized to levels similar to controls without reflux (p = 0.74). Similar results were observed in the prospectively obtained fresh frozen tissue.

CONCLUSIONS

Cox-2 gene expression is increased in the distal esophageal squamous mucosa of most patients with GERD, and the elevation was similar whether there was mucosal injury in the form of esophagitis or Barrett's or no visible mucosal injury. This suggests that increased Cox-2 expression may serve as a molecular marker of reflux disease. The increased Cox-2 expression in patients with reflux was usually normalized following antireflux surgery. These findings demonstrate for the first time that gene expression can be altered by surgical correction of reflux. Thus, in addition to symptom control and improvement in the quality of life, perhaps future studies assessing the efficacy of antireflux therapy should also focus on the impact of the therapy on gene expression in the esophageal squamous mucosa.

DNA methyltransferases messenger RNA expression and aberrant methylation of CpG islands in non-small-cell lung cancer: association and prognostic value

BACKGROUND

A significant association between aberrant methylation in regulatory regions of tumor suppressor genes and clinical outcome in various different cancer types has been described. The molecular events for this epigenetic alteration still remain unknown. Evidence suggests that overexpression of DNA methyltransferases (DNMTs) is one potential mechanism for hypermethylation.

PATIENTS AND METHODS

Therefore, we investigated the influence of gene expression levels of the 3 DNMT isoforms (DNMT1, DNMT3a, and DNMT3b) and the hypermethylation of adenomatous polyposis coli (APC), the death-associated protein kinase (DAPK), glutathione S-transferase Pi (GSTPI), and the DNA repair gene O6-methylguanine DNA transferase (MGMT) in the pathogenesis and prognosis of patients with non-small cell lung cancer and determined their association to each other. Using a quantitative real-time reverse-transcriptase polymerase chain reaction, we measured messenger RNA expression of DNMT1, DNMT3a, and DNMT3b and DNA hypermethylation of APC, DAPK, GSTPI, and MGMT in 91 matching tumor and nonmalignant lung tissue samples from patients with curatively resected non-small-cell lung cancer.

RESULTS

In tumor tissue, the expression of all 3 DNMT isoforms was significantly higher compared with matched normal-appearing tissue (P < 0.001). Hypermethylation in tumor tissue was found in 95% for APC, in 92% for DAPK, in 18% for GSTPI, and in 38% for MGMT.

CONCLUSION

No correlation was found between the DNMT messenger RNA expression and DNA hypermethylation status in tumor tissues. Multivariate analysis revealed DNA hypermethylation status and TNM stage as independent prognostic factors.