ABSTRACT
BACKGROUND: Breast cancer is the most frequent female malignancy in Thailand. Prolactin (PRL) and prolactin receptor (PRLR) play an important role in normal breast development and carcinogenesis of breast cancer. There are two major isoforms of PRLR, consisting of long-form (LF-PRLR) and short-form (SF-PRLR) that stimulate different signaling pathways. This study aims to explore the associations between all PRLR isoforms (all-PRLR) and LF-PRLR with clinicopathological parameters in breast cancer patients. METHODS: A total of 340 patients were recruited from January 2009 to December 2015. Expressions of PRLR in breast cancer tissue were determined by immunohistochemistry using specific antibodies that recognize different domains of PRLR (B6.2 for all-PRLR and H-300 for LF-PRLR). The associations between all-PRLR and LF-PRLR expressions with clinicopathological parameters were evaluated. RESULTS: Expression of all-PRLR was observed in 86.2% of all patients while LF-PRLR expression was observed in 54.4%. All-PRLR was co-expressed with estrogen receptor (ER) and progesterone receptor (PR). LF-PRLR expression was associated with high grade tumor and human epidermal growth factor receptor-2 (HER2) overexpression (P=0.010 and <0.001, respectively). Subgroup analysis revealed that LF-PRLR expression was the independent predictor for lower disease-free survival (DFS) in node-negative breast cancer patients with high expression of all-PRLR [hazard ratio (HR): 5.224, 95% confidence interval (CI): 1.089-25.064, P=0.039]. CONCLUSIONS: The presence of LF-PRLR in the patients with high expression of all-PRLR was associated with adverse outcome. Evaluation of all-PRLR and LF-PRLR might be used as novel prognosticators in node-negative breast cancers.
ABSTRACT
Androgen receptor (AR) was associated with favourable outcome in luminal breast cancer. However, the role of AR in non-luminal breast cancer remains inconclusive. The aim of the present study was to evaluate the clinical significance of the AR and its regulatory pathway in non-luminal subtypes of breast cancer. In total, 284 breast cancer patients were recruited from January 2007 to January 2016. Tissue microarrays were constructed from archival paraffin blocks and assessed for AR and its regulatory molecule, Lin28, by immunohistochemistry. The association between AR and Lin28 expression and clinicopathological parameters was analyzed. Results showed that AR and Lin28 were co-expressed. No association between these proteins and clinicopathological parameters, and survival outcome was found. However, a higher proportion of the patients with AR and Lin28 expression were observed in HER2 subtype. In conclusion, Lin28 may be a novel marker for prognosis and targeted for treatment in HER2 subtype breast cancer.
