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Cancer research

Genetic Markers Predict Chemotherapy Resistance in Gastric Cancer

Strategic Insights

— 2 min read

Recent research from Osaka, Japan, has identified two genetic markers that can predict resistance to chemotherapy in gastric carcinoma patients. The study, published in the Annals of Surgical Oncology, found that tumors with allelic imbalance at the p53 locus and/or microsatellite instability (MSI) were significantly more resistant to neoadjuvant chemotherapy. This discovery could lead to more effective treatment strategies for patients with gastric cancer.

Key Takeaways:

  • The study tested 23 patients with gastric carcinoma who were treated with neoadjuvant chemotherapy, and genetic studies were performed to detect allelic imbalance, microsatellite instability, and K-ras mutation.
  • A clinical response was observed in 13 of 23 patients, with Kaplan-Meier survival curve showing a significantly higher likelihood of overall survival in the clinical responder group.
  • In 23 resection specimens, 10 tumors presented AI at the p53 locus and/or MSI, with 8 of the 10 tumors being nonresponders, while 12 of 13 tumors without p53 AI or MSI were responders (p=0.0007).
  • Tumors with AI at the p53 locus and/or MSI were significantly more resistant to neoadjuvant chemotherapy, with no relationship found between K-ras mutations and responses.
  • The analysis for p53 AI and MSI might represent a clinically useful approach to predicting the response to neoadjuvant FP chemotherapy in gastric carcinoma.
  • The study was conducted by M. Yashiro and colleagues at Osaka City University, Department of Surgical Oncology.

Statistics:

  • 23 patients with gastric carcinoma were treated with neoadjuvant chemotherapy.
  • 15 of 23 patients had pretreatment biopsy specimens before neoadjuvant chemotherapy, and resected tumors were obtained from all 23.
  • A clinical response was observed in 13 out of 23 patients (56.5% response rate).
  • Overall survival was significantly higher in the clinical responder group (p=0.0165).
  • 10 out of 23 tumors presented AI at the p53 locus and/or MSI (43.5% frequency).
  • 8 out of 10 nonresponders had AI at the p53 locus and/or MSI (80% frequency).
  • 12 out of 13 responders did not have p53 AI or MSI (92.3% frequency).
  • 7 out of 15 tumors with pretreatment biopsy specimens had p53 AI and/or MSI (46.7% frequency).
  • 6 out of 7 nonresponders had p53 AI and/or MSI (85.7% frequency).

Sources:

  • Yashiro, M., et al. (2009). Allelic imbalance at p53 and microsatellite instability are predictive markers for resistance to chemotherapy in gastric carcinoma. Annals of Surgical Oncology, 16(10), 2926-35.
  • Biotech Week editors (2010). Genetic markers predict chemotherapy resistance in gastric cancer. Biotech Week via NewsRx.com.

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