Prediction of response to neoadjuvant chemotherapy in carcinomas of the upper gastrointestinal tract

GADD45A expression is correlated with patient prognosis in esophageal cancer

The prognosis of patients with esophageal cancer remains poor, and the tumor-node-metastasis classification system is not sufficient for predicting patient prognoses. Therefore, the identification of novel predictive markers for esophageal cancer is required. The present study investigated the clinicopathological significance of growth arrest and DNA damage-inducible 45α (GADD45A) and p53 in resectable esophageal squamous cell carcinoma (ESCC). The study consisted of 62 patients with esophageal cancer who underwent surgery between 2001 and 2007. The expression of the GADD45A gene product (GADD45A) and the p53 protein was analyzed by immunohistochemistry. The correlations among GADD45A expression, clinicopathological factors and prognosis were then analyzed in the patients with ESCC. GADD45A and p53 were expressed in 56.5% (35/62) and 48.4% (30/62) of patients, respectively. The expression of GADD45A did not show a marked correlation with that of p53. However, GADD45A expression correlated with pathological stage (stage 0-I vs. stages II-IV; P=0.014) and did not correlate with the tumor (T) or node (N) status. Furthermore, patients who were positive for GADD45A exhibited a significantly higher survival rate than those who were negative for GADD45A (log-rank test, P=0.009). Multivariate analysis indicated that T status, N status and GADD45A expression were significant variables predicting survival (hazard ratio, 2.486; 95% confidence interval, 1.168-5.290; P=0.018). Overall, GADD45A expression significantly affected the survival of patients with ESCC, and the reduced expression of GADD45A was correlated with a poor prognosis following curative surgery in these patients.

Correlation between expressions of ERCC1/TS mRNA and effects of gastric cancer to chemotherapy in the short term

PURPOSE

To study the correlation between expression levels of ERCC1/TS mRNA and the susceptibility of preoperative chemotherapy for patients with gastric cancer.

METHODS

A total of forty cases with advanced gastric cancer of T3-4N1-2M0 were treated with preoperative chemotherapy according to FLEEOX regimen based on endarterial-intravenous coadministration. Sufficient, fresh gastric tissue specimens were obtained with the help of gastroscope, and the expression levels of ERCC1/TS mRNA were detected by qRT-PCR before chemotherapy. The chemotherapeutic response was evaluated with Choi Criteria after chemotherapy, and pathologic remission extent was observed after surgery. The correlation between the expression levels of ERCC1/TS mRNA before chemotherapy and the chemotherapeutic effect based on imageology and pathology was analyzed.

RESULTS

The response rate of Chemotherapy in this cohort was 80.0 % based on imageology and 51.43 % based on pathology. The expression levels of ERCC1/TS mRNA were significantly associated with imageology remission extent (P = 0.033, P = 0.025) and pathologic remission extent (P = 0.044, P = 0.016), respectively. The chemotherapeutic effect on patients with low-expression levels of ERCC1/TS mRNA was better.

CONCLUSIONS

From the perspective of pathology and imageology evaluating the preoperative chemotherapeutic response for patients with gastric cancer, ERCC1 and TS were used as the molecular predictors and provided prognostic information in this study.

Impact of ABCB1 C3435T polymorphism on lymph node regression in multimodality treatment of locally advanced esophageal cancer

AIMS

Neoadjuvant treatment strategies have been developed to improve the survival of patients with locally advanced esophageal cancer. Since patients with major histopathological response are the ones who mainly benefit from this therapy, we are looking for causes of nonresponse. The multidrug resistance protein ABCB1 belongs to the ATP-binding cassette superfamily of membrane transporters. By exporting positively charged drugs it plays a role in the acquisition of resistance in anticancer therapy. We examined the ABCB1 gene polymorphism C3435T to predict response and prognosis to neoadjuvant radiochemotherapy (cisplatin, 5-fluorouracil and 36 Gy) in locally advanced esophageal cancer patients.

MATERIALS & METHODS

A total of 262 patients (216 male; 46 female; median age: 62 years) with locally advanced esophageal cancer (squamous cell cancer: n = 116, adenocarcinoma: n = 146) were included in this study. All patients received a neoadjuvant radiochemotherapy (36.0 Gy, 5-fluorouracil, cisplatin) followed by surgery. Histomorphologic regression was classified according to the Cologne Regression Grade with major response being classifed as having less than 10% vital tumor cells (n = 107) and minor response when 10% or more vital tumor cells (n = 155) were detected in the surgical specimen. Genomic DNA was extracted from paraffin-embedded tissues of all study patients. Allelic genotyping was performed for ABCB1 rs1045642 by real-time PCR using two allele-specific TaqMan(®) probes in competition. Allelic genotyping was correlated with therapy response and prognosis.

RESULTS

Allelic discrimination revealed a TT genotype in 27%, a CC in 19% and a CT genotype in 54% of the study patients. This SNP was not predictive for response of the primary tumor to neoadjuvant radiochemotherapy. The ABCB1 genotype CC was associated with lymph node formation (p = 0.012) and distant metastases (p = 0.019). Patients with a TT genotype exhibited a significantly less positive lymph node status (ypN1 35%) after chemoradiation compared with patients with a CC (ypN1 = 60%) or CT (ypN1 = 46%) genotype. Moreover, patients bearing the TT genotype exhibited no distant metastasis, while five patients with a CC and two patients with CT genotype had distant metastases. In Kaplan-Meier curves, adenocarcinoma patients with a CC genotype showed a worse survival rate than patients with TT or CT (p = 0.048).

CONCLUSION

Our data supports the impact of ABCB1 on effectiveness of esophageal cancer treatment. SNPs of ABCB1 could be helpful in predicting lymph node regression in the multimodality treatment of locally advanced esophageal cancer.

Ku80 gene G-1401T promoter polymorphism and risk of gastric cancer

AIM: To evaluate the possible relationship between the Ku80 gene polymorphism and the risk of gastric cancer in China.

METHODS: In this hospital-based case-control study of gastric cancer in Jiangsu Province, China, we investigated the association of the Ku80 G-1401T (rs828907) polymorphism with gastric cancer risk. A total of 241 patients with gastric cancer and 273 age- and sex-matched control subjects were genotyped and analyzed by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS: The frequencies of genotypes GG, GT and TT were 65.6%, 22.8% and 11.6% in gastric cancer cases, respectively, and 75.8%, 17.6% and 6.6% in controls, respectively. There were significant differences between gastric cancer and control groups in the distribution of their genotypes (P = 0.03) and allelic frequencies (P = 0.002) in the Ku80 promoter G-1401T polymorphism.

CONCLUSION: The T allele of Ku80 G-1401T may be associated with the development of gastric cancer.

Allelic imbalance at p53 and microsatellite instability are predictive markers for resistance to chemotherapy in gastric carcinoma

BACKGROUND

Combined treatment with 5-fluorouracil and cisplatin (FP chemotherapy) is an effective neoadjuvant regimen for gastric carcinoma. However, it is ineffective in half of all patients. This study tests the hypothesis that genetic markers might identify those patients with gastric cancer who would respond to neoadjuvant FP chemotherapy.

MATERIALS AND METHODS

A total of 23 patients with gastric carcinoma were treated with neoadjuvant chemotherapy. Pretreatment biopsy specimens before neoadjuvant chemotherapy were obtained from 15 of 23 patients, and resected tumors were obtained from all 23. Genetic studies were performed to detect allelic imbalance (AI), microsatellite instability (MSI), and K-ras mutation.

RESULTS

A clinical response was observed in 13 of 23 patients. Kaplan-Meier survival curve showed that clinical responder group had a significantly higher likelihood of overall survival (P = 0.0165), compared with nonresponder group. In 23 resection specimens, 10 of 23 tumors presented AI at the p53 locus and/or MSI; 8 of the 10 tumors were nonresponders, while 12 of 13 tumors without p53 AI or MSI were responders (P = 0.0007). In 15 pretreatment biopsy specimens, 8 tumors had p53 AI and/or MSI; 7 of the 8 tumors were nonresponders, while 6 of 7 tumors without p53 AI or MSI were responders to preoperative chemotherapy (P = 0.008). Tumors with AI at the p53 locus and/or MSI were significantly more resistant to neoadjuvant chemotherapy. No relationship was found between K-ras mutations and responses.

CONCLUSIONS

Analysis for p53 AI and MSI might represent a clinically useful approach to predicting the response to neoadjuvant FP chemotherapy in gastric carcinoma.

Circulating lymphangiogenic growth factors in gastrointestinal solid tumors, could they be of any clinical significance?

Metastasis is the principal cause of cancer mortality, with the lymphatic system being the first route of tumor dissemination. The glycoproteins VEGF-C and VEGF-D are members of the vascular endothelial growth factor (VEGF) family, whose role has been recently recognized as lymphatic system regulators during embryogenesis and in pathological processes such as inflammation, lymphatic system disorders and malignant tumor metastasis. They are ligands for the VEGFR-3 receptor on the membrane of the lymphatic endothelial cell, resulting in dilatation of existing lymphatic vessels as well as in vegetation of new ones (lymphangiogenesis). Their determination is feasible in the circulating blood by immunoabsorption and in the tissue specimen by immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR). Experimental and clinicopathological studies have linked the VEGF-C, VEGF-D/VEGFR3 axis to lymphatic spread as well as to the clinical outcome in several human solid tumors. The majority of these data are derived from surgical specimens and malignant cell series, rendering their clinical application questionable, due to subjectivity factors and post-treatment quantification. In an effort to overcome these drawbacks, an alternative method of immunodetection of the circulating levels of these molecules has been used in studies on gastric, esophageal and colorectal cancer. Their results denote that quantification of VEGF-C and VEGF-D in blood samples could serve as lymph node metastasis predictive biomarkers and contribute to preoperative staging of gastrointestinal malignancies.

Predictors of response and survival for neoadjuvant treated patients with esophageal adenocarcinoma

Mainly patients with advanced esophageal adenocarcinoma who respond to neoadjuvant chemotherapy show a significant survival benefit after resection. Therefore, prediction of response before treatment is desirable. The aim of this study was to assess genetic predictors of response and survival for patients with esophageal adenocarcinoma prior to neoadjuvant therapy. Thirty-two patients with advanced esophageal adenocarcinoma who underwent neoadjuvant therapy with resection of their tumor were analyzed for thymidylate synthase (TS), excision repair cross complementing (ERCC1) and Gluthatione S-transferase (GSTP-1) mRNA levels prior to the treatment. These results were analyzed in regards of response and survival. In total, 18 patients responded to this protocol. Seventeen of those did show a gene expression level at or below the respective median of at least one gene. This had a profound impact on survival, demonstrating an increase in survival for patients who have TS, ERCC1, or GSTP-1 mRNA level at or below the median. These results demonstrate a potential predictive value of a gene expression profile available prior to therapy. These data have to be confirmed by a larger prospective trial.

Cancer stem cells as the engine of unstable tumor progression

Genomic instability is considered by many authors the key engine of tumorigenesis. However, mounting evidence indicates that a small population of drug resistant cancer cells can also be a key component of tumor progression. Such cancer stem cells would define a compartment effectively acting as the source of most tumor cells. Here we study the interplay between these two conflicting components of cancer dynamics using two types of tissue architecture. Both mean field and multicompartment models are studied. It is shown that tissue architecture affects the pattern of cancer dynamics and that unstable cancers spontaneously organize into a heterogeneous population of highly unstable cells. This dominant population is in fact separated from the low-mutation compartment by an instability gap, where almost no cancer cells are observed. The possible implications of this prediction are discussed.