1658P - Expression and prognostic significance of mesothelin in HER-2-positive and triple-negative breast cancer patients

Date 28 September 2014
Event ESMO 2014
Session Poster Display session
Topics Breast Cancer
Translational Research
Basic Principles in the Management and Treatment (of cancer)
Presenter ibrahim vedat Bayoglu
Citation Annals of Oncology (2014) 25 (suppl_4): iv564-iv573. 10.1093/annonc/mdu359
Authors I.V. Bayoglu1, B. Kucukzeybek2, Y. Küçükzeybek1, I. Yildiz1, M. Akyol1, U. Varol1, A. Alacacioglu1, L. Demir1, A. Dirican1, Y. Yildiz1, M.O. Tarhan1
  • 1Medical Oncology, Izmir Katip Celebi University Ataturk Training and Research Hospital, 35500 - izmir/TR
  • 2Pathology, Izmir Katip Celebi University Ataturk Training and Research Hospital, 35500 - izmir/TR

Abstract

Aim

Mesothelin expression has been shown in many tumours and it is an ideal tumor-associated marker for the development of targeted therapy due to its limited expression in normal tissues. Expression of mesothelin has been revealed that affects the signal transduction processes and central pathways in tumorigenesis. The aim of this study was to evaluate mesothelin expression in HER2-positive and triple-negative breast cancer (TNBC) and its correlation with survival outcomes.

Methods

Mesothelin expression was completed by using immunohistochemistry (IHC) and was quantified by the H score. H score>10 was considered positive. ER(-) and PR(-) were defined with IHC (<1% positive cells). A positive HER2 result was defined with IHC staining of +3 (>10% of invasive tumor cells) and/or fluorescent in situ hybridization (FISH) [intermediate levels of staining (2+) were confirmed by FISH]. Patient and tumor characteristics were compared by mesothelin expression. The Kaplan-Meier product limit method was used to estimate survival outcomes. Cox proportional hazards models were used to adjust for patient and tumor characteristics.

Results

The median age was 52 years. Among 123 patients, 52 (42%) were HER2-positive and 71 (58%) were TNBC. Mesothelin expression was determined positive in 30 (42.3%) of 71 patients in TNBC group and in two (3.8%) of 52 patients in HER2-positive group. Although, the expression of mesothelin in patients with lymph node metastasis was observed to be higher than in those with without metastasis, there were no significant differences between mesothelin positive and negative cohorts in terms of patient and/or tumor characteristics with the exception of high tumor nuclear grade in mesothelin positive group (P< 0.005). Median DFS 46.5 and median OS 70.1 months were determined for all patients. Median DFS and OS were 46 and 70.1 months in mesothelin positive group and 41 and 74.5 months in mesotheline negative group, respectively. The differences were not statistically significant (p>0.05). Mesothelin expression was not an independent predictor for survival outcomes.

Conclusions

Mesothelin expression was identified in 42.3% of TNBC patients and demonstrated a strong association with tumor grade of these patients. However, it was not correlated with prognosis.

Disclosure

All authors have declared no conflicts of interest.