Abstract 44P
Background
Intracellular signalling pathways play a role for treatment response and outcome for patients with breast cancer (BC).
Methods
We analysed phosphorylated MAPK (pJNK, pERK, pp38) and pAkt with a commercial multiplex enzyme-linked immunosorbent assay (ELISA) (Luminex®) and M30, a marker of apoptosis, in 449 patients with primary ER-positive BC. The aim was to determine the relation between pMAPK, proliferation, apoptosis, and survival in Invasie Lobular Carcinoma (ILC) and non-Invasive Lobular Carcinoma (non-ILC).
Results
Medium follow up was 18.9 years and ILC and non-ILC had an equal Relapse Free Survival (RFS) (p=0.68). In the whole population pAkt was the only kinase with prognostic information; patients with absent/low levels of pAkt had a worse RFS (p=0.016). A multivariate analysis showed tumour size (HR=1.8) (p=0.0016), nodal status (HR=2.8) (p<0.001) and absent/low pAkt (HR=0.69) (p=0.059) as independent prognostic factors. There was a difference between ILC and non-ILC concerning expression of estrogen receptor (ER) (p=0.033), apoptosis (p<0.001), pERK (p=0.004), pJNK (p<0.001) and pp38 (p=0.005) whilst nodal status, Progesteron Receptor (PGR), proliferation rate and pAKT were equal. ILC had a trend towards larger size, but this did not reach statistical significance (p=0.059). Proliferation was correlated to RFS in non-ILC (p<0.001) but not in ILC (p=0.94). pMAPK were not correlated to RFS when patients were split in ILC and non-ILC.
Conclusions
We show differences in expression of activated MAPKs in ILC and non-ILC. Despite lower proliferation and apoptosis, we could not show any correlation to survival in ILC, but this may indicate a more stem cells like behaviour. ER-positive ILC and non-ILC have similar survival, pAkt was the only kinase with prognostic information.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.