Increased tumor cell expression of Axl is a marker of aggressive features in breast cancer among African women

• Published in: APMIS : acta pathologica, microbiologica et immunologica Scandinavica Vol. 123; no. 8; pp. 688 - 696
• Main Authors: Ahmed, Lavina, Nalwoga, Hawa, Arnes, Jarle B., Wabinga, Henry, Micklem, David R., Akslen, Lars A.
• Format: Journal Article
• Language: English
• Published: Denmark Blackwell Publishing Ltd 01.08.2015; Wiley Subscription Services, Inc
• Subjects: African Continental Ancestry Group - genetics; angiogenesis; Axl; Basal-like breast cancer; Biomarkers, Tumor - genetics; Biomarkers, Tumor - metabolism; Breast Neoplasms - diagnosis; Cadherins - genetics; Cadherins - metabolism; Cell Line, Tumor; Cell Proliferation; Female; Humans; Middle Aged; Neovascularization, Pathologic; Prognosis; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins - metabolism; Receptor Protein-Tyrosine Kinases - genetics; Receptor Protein-Tyrosine Kinases - metabolism; Receptors, Estrogen - genetics; Receptors, Estrogen - metabolism; Tumor Suppressor Protein p53 - genetics; Tumor Suppressor Protein p53 - metabolism; Axl; angiogenesis; Basal-like breast cancer
• ISSN: 0903-4641; 1600-0463
• DOI: 10.1111/apm.12403

Axl, a receptor tyrosine kinase belonging to the Tyro/Axl/Mer (TAM) family, has been shown to be overexpressed in breast cancer with poor outcome. Moreover, Axl was associated with a basal‐like phenotype (BLP) in these tumors. Our aim was to investigate Axl expression in breast cancers from an African population since these tumors are known to be aggressive and have a high frequency of the basal‐like phenotype. We studied 170 paraffin‐embedded breast carcinoma cases by tissue microarrays and immunohistochemical methods. In total, 128 tumor cases (75%) had strong Axl expression and 42 cases (25%) had weak or negative staining. Strong expression of Axl was associated with high tumor grade (p < 0.0005), estrogen receptor (ER) negativity (p = 0.024), p53 expression (p = 0.004), P‐cadherin positivity (p = 0.017), and basal‐like phenotypic profiles BLP2 (p = 0.033) and BLP3 (p = 0.022). In addition, Axl overexpression also showed an association with markers of tumor cell proliferation and tumor angiogenesis. In conclusion, our findings indicate strong expression of Axl in a high proportion of breast cancer cases among African women and associations with markers of aggressive features, indicating poor prognosis. These findings suggest Axl as a potential therapeutic target in this population.