Overexpression of Antiapoptotic MCL-1 Predicts Worse Overall Survival of Patients With Non-small Cell Lung Cancer

Anticancer Res. 2020 Feb;40(2):1007-1014. doi: 10.21873/anticanres.14035.

Abstract

Background/aim: Myeloid cell leukemia-1 (MCL-1) is a member of the B-cell lymphoma-2 (Bcl-2) family of proteins, which regulate the intrinsic (mitochondrial) apoptotic cascade. MCL-1 inhibits apoptosis, which may be associated with resistance to cancer therapy. Therefore, in this study, the clinical role of MCL-1 in non-small cell lung cancer (NSCLC) was explored.

Patients and methods: This retrospective study included 80 patients with stage 1-3A NSCLC, who underwent surgery without preoperative treatment between 2010 and 2011. MCL-1 expression and Ki-67 index were determined via immunohistochemical staining. Apoptotic index (AI) was determined via terminal deoxynucleotidyl transferase dUTP nick end labeling.

Results: The receiver operating characteristic curve analysis (area under curve=0.6785) revealed that MCL-1 expression in 30.0% of the NSCLC tumor cells was a significant cut-off for predicting prognosis. Tumors were considered MCL-1-positive if staining was observed in >30% of the cells. Thirty-six tumors (45.0%) were MCL-1-positive. However, there were no significant differences between MCL-1 expression and clinical variables. AI was lower in MCL-1-positive (2.2±3.6%) than in MCL-1-negative (5.2±7.9%) tumors, although the difference was not significant (p=0.1080). The Ki-67 index was significantly higher in MCL-1-positive than in MCL-1-negative tumors (18.0% vs. 3.0%; p<0.001). Five-year survival rate was significantly worse in patients with MCL-1-positive tumors (68.3%) than in those with MCL-1-negative tumors (93.1%, p=0.0057). Univariate [hazard ratio (HR)=5.041, p=0.0013], and multivariate analyses revealed that MCL-1 expression was a significant prognostic factor (HR=3.983, p=0.0411).

Conclusion: MCL-1 expression in NSCLC cells correlated inversely with AI and positively with Ki-67 index. MCL-1 may serve as a potential prognostic biomarker and a novel therapeutic target in NSCLC.

Keywords: Apoptosis; myeloid cell leukemia-1; non-small cell lung cancer; prognosis; survival.

MeSH terms

  • Adult
  • Aged
  • Apoptosis / genetics
  • Biomarkers, Tumor*
  • Carcinoma, Non-Small-Cell Lung / genetics*
  • Carcinoma, Non-Small-Cell Lung / mortality*
  • Carcinoma, Non-Small-Cell Lung / pathology
  • Female
  • Gene Expression*
  • Humans
  • Lung Neoplasms / genetics*
  • Lung Neoplasms / mortality*
  • Lung Neoplasms / pathology
  • Male
  • Middle Aged
  • Myeloid Cell Leukemia Sequence 1 Protein / genetics*
  • Myeloid Cell Leukemia Sequence 1 Protein / metabolism
  • Prognosis
  • Proportional Hazards Models
  • ROC Curve

Substances

  • Biomarkers, Tumor
  • Myeloid Cell Leukemia Sequence 1 Protein