XPG mRNA expression levels modulate prognosis in resected non-small-cell lung cancer in conjunction with BRCA1 and ERCC1 expression

Clin Lung Cancer. 2009 Jan;10(1):47-52. doi: 10.3816/CLC.2009.n.007.

Abstract

Background: Molecular markers can help identify patients with early-stage non-small-cell lung cancer (NSCLC) with a high risk of relapse. Excision repair cross-complementing 1 (ERCC1), Xeroderma pigmentosum group G (XPG), and breast cancer 1 (BRCA1) are involved in DNA damage repair, whereas ribonucleotide reductase M1 (RRM1) is implicated in DNA synthesis. Expression levels of these molecules might therefore have a prognostic role in lung cancer.

Patients and methods: We examined ERCC1, RRM1, XPG, and BRCA1 mRNA levels by real-time quantitative polymerase chain reaction in 54 patients with stage IB-IIB resected NSCLC. A strong correlation was observed between the 4 genes.

Results: For patients with low BRCA1, regardless of XPG mRNA expression levels, disease-free survival (DFS) was not reached. For patients with intermediate/high BRCA1 and high XPG, DFS was 50.7 months. However, for patients with intermediate/high BRCA1 and low/intermediate XPG, DFS decreased to 16.3 months (P = .002). Similar differences were observed in overall survival, with median survival not reached for patients with low BRCA1, regardless of XPG levels, or for patients with intermediate/high BRCA1 and high XPG. Conversely, for patients with intermediate/high BRCA1 levels and low/intermediate XPG levels, median survival dropped to 25.5 months (P = .007).

Conclusion: BRCA1 and XPG were identified as independent prognostic factors for both median survival and DFS. High BRCA1 mRNA expression confers poor prognosis in early NSCLC, and the combination of high BRCA1 and low XPG expression still further increases the risk of shorter survival. These findings can help optimize the customization of adjuvant chemotherapy.

MeSH terms

  • Aged
  • Aged, 80 and over
  • BRCA1 Protein / genetics
  • BRCA1 Protein / metabolism*
  • Carcinoma, Non-Small-Cell Lung / genetics*
  • Carcinoma, Non-Small-Cell Lung / pathology
  • Carcinoma, Non-Small-Cell Lung / surgery
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Disease-Free Survival
  • Endonucleases / genetics
  • Endonucleases / metabolism*
  • Female
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Lung Neoplasms / genetics*
  • Lung Neoplasms / pathology
  • Lung Neoplasms / surgery
  • Male
  • Middle Aged
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Polymerase Chain Reaction
  • Prognosis
  • RNA, Messenger / genetics
  • Survival Rate
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*

Substances

  • BRCA1 Protein
  • DNA excision repair protein ERCC-5
  • DNA-Binding Proteins
  • Nuclear Proteins
  • RNA, Messenger
  • Transcription Factors
  • ERCC1 protein, human
  • Endonucleases