Neutrophil gelatinase-associated lipocalin (NGAL) is a small, secreted glycoprotein with proposed functions in cell proliferation, survival and morphogenesis. NGAL is expressed in a variety of tumor types including breast carcinomas, but it is not known whether NGAL contributes directly to breast cancer progression. This study examines the relationship between NGAL expression in breast carcinomas and established clinical prognostic markers as well as clinical outcome. Using immunohistochemistry in tissue microarrays containing well characterized tumor samples from 207 breast cancer patients, NGAL was detected in 68 breast carcinomas in a cytoplasmic location. NGAL expression correlated strongly with negative steroid receptor status, HER-2/neu overexpression, poor histologic grade, the presence of lymph node metastases and a high Ki-67 proliferation index. In univariate survival analysis, NGAL expression was associated with decreased disease-specific survival and decreased disease-free survival in the entire cohort. In multivariate analysis, NGAL remained an independent prognostic marker for disease-free survival. In a subset of patients with estrogen receptor positive tumors, NGAL was significantly associated with decreased disease-free survival. The results show that NGAL expression is a predictor of poor prognosis in primary human breast cancer and suggest that NGAL detection may provide information for risk assessment and identify a subset of patients requiring more aggressive adjuvant therapy.

We previously identified HSulf-1 as a down-regulated gene in several tumor types including ovarian, breast, and hepatocellular carcinomas. Loss of HSulf-1, which selectively removes 6-

Breast carcinoma invasion is associated with prominent alterations in stromal fibroblasts. Carcinoma-associated fibroblasts (CAF) support and promote tumorigenesis, whereas normal mammary fibroblasts (NF) are thought to suppress tumor progression. Little is known about the difference in gene expression between CAF and NF or the patient-to-patient variability in gene expression. Paired CAF and NF were isolated from six primary human breast carcinoma specimens. RNA was extracted from low-passage cultures of CAF and NF and analyzed with Affymetrix Human Genome U133 Plus 2.0 arrays. The array data were examined with an empirical Bayes model and filtered according to the posterior probability of equivalent expression and fold difference in expression. Twenty-one genes (27 probe sets) were up-regulated in CAF, as compared to NF. Known functions of these genes relate to paracrine or intracellular signaling, transcriptional regulation, extracellular matrix and cell adhesion/migration. Ten genes (14 probe sets) were down-regulated in CAF, including the pluripotency transcription factor KLF4. Quantitative RT-PCR analysis of 10 genes validated the array results. Immunohistochemical staining for three gene products confirmed stromal expression in terms of location and relative quantity. Surprisingly, the variability of gene expression was slightly higher in NF than in CAF, suggesting inter-individual heterogeneity of normal stroma.

Our findings reveal an unprecedented role of CB2 as a pivotal regulator of HER2 pro-oncogenic signaling in breast cancer, and they suggest that CB2 may be a biomarker with prognostic value in these tumors.