I found some papers stating a low level of expression as a claudin-low subtype and others with a high level of expression as a basal subtype, using Immunohistochemical techniques.
http://insights.sagepub.com/the-expression-patterns-of-er-pr-her2-ck56-egfr-ki-67-and-ar-by--immun-article-a2068
http://exp-oncology.com.ua/article/5877/expression-of-biomarkers-related-to-cell-adhesion-metastasis-and-invasion-of-breast-cancer-cell-lines-of-different-molecular-subtype