Statistical association of basal cell keratins with metastasis-inducing proteins in a prognostically unfavorable group of sporadic breast cancers.

Two subgroups of invasive breast carcinomas have been identified with a poor prognosis in different patient cohorts: the basal-like category and the subgroup containing proteins capable of inducing metastasis in experimental rodents, the metastasis-inducing proteins (MIPs). Here we identify by immunohistochemical staining for cytokeratin CK5/6 or CK14 the basal-like subgroup in a set of 297 primary invasive breast carcinomas in which the staining profile for the MIPs S100A4, osteopontin, anterior gradient-2, and S100P has already been established. Monoclonal antibodies to CK5/6 or CK14 specifically stain 31% to 34% of the primary carcinomas. These positively stained tumors are highly significantly associated with premature death of the patient (Wilcoxon statistics, P < 0.0001), the increased relative risk being approximately 5.6-fold. Positive staining for either cytokeratin is very significantly associated with that for each of the four MIPs separately and with loss of staining for the Fanconi anemia protein FANCD2 (corrected Fisher's exact test, P < 0.0007). There is no significant correlation with the remaining tumor variables tested, including staining for the estrogen receptor α, progesterone receptor, and c-erbB-2. These results show that the basal cytokeratin-like carcinomas contain many of the MIPs and that these may arise by their selection for tumors with an inherent deficiency in the FANC/BRCA pathway of DNA repair.

Significance of the Fanconi anemia FANCD2 protein in sporadic and metastatic human breast cancer.

FANCD2, a pivotal protein in the Fanconi anemia and BRCA pathway/network, is monoubiquitylated in the nucleus in response to DNA damage. This study examines the subcellular location and relationship with prognostic factors and patient survival of FANCD2 in breast cancer. Antibodies to FANCD2 were used to immunocytochemically stain 16 benign and 20 malignant breast specimens as well as 314 primary breast carcinomas to assess its association with subcellular compartment and prognostic factors using Fisher's Exact test or with patient survival over 20 years using Wilcoxon-Gehan statistics. Immunoreactive FANCD2 was found in the nucleus and cytoplasm of all 16 benign tissues, but nuclear staining was lost from a significant 19/20 malignant carcinomas (P < 0.0001). Antibodies to FANCD2 stained the cytoplasm of 196 primary carcinomas, leaving 118 as negatively stained. Negative cytoplasmic staining was significantly associated with positive staining for the metastasis-inducing proteins S100A4, S100P, osteopontin, and AGR2 (P < or = 0.002). Survival of patients with FANCD2-negative carcinomas was significantly worse (P < 0.0001) than those with positively stained carcinomas, and only 4% were alive at the census date. Multivariate regression analysis identified negative staining for cytoplasmic FANCD2 as the most significant indicator of patient death (P = 0.001). Thus FANCD2's cytoplasmic loss in the primary carcinomas may allow the selection of cells overexpressing proteins that can induce metastases before surgery.

Prognostic significance of the metastasis-associated protein osteopontin in human breast cancer.

The adhesive glycophosphoprotein (OPN) is capable of inducing metastasis in rodent models ofbreast cancer. We now show that a monoclonal antibody to rat OPN recognizes specifically human OPN using Western blotting techniques andused it to assess the prognostic significance of OPN in primary tumors of a group of 333 patients treated between 1976 and 1982 for operable stage I and stage II breast cancer. The antibody stains immunocytochemically normal breast tissue weakly but pregnant/lactating tissue and 66% of the carcinomas strongly, leaving the remaining 34% as negatively stained. In addition to the carcinoma cells, some host reactive stromal cells, macrophages, lymphocytes, and blood vessels are also stained, but these have been excluded in the following analyses. There is a significant association of staining of carcinomas for OPN with some tumor variables reported previously to be associated with patient outcome: high histological grade (P = 0.024), staining for c-erbB-3 (P < 0.001), p53 (P = 0.014), pS2 (P = 0.025), and borderline significance for progesterone receptor (P = 0.089). The association of staining for OPN with survival times of the patients has been evaluated using life tables over 14-20 years of follow-up (mean 16 years) and analyzed using generalized Wilcoxon statistics. Of the patients who have been classified as OPN-negative, 94% are alive, but only 26% of those classified as OPN-positive are alive after 19 years of follow-up. This association is highly significant (P < 0.0001); the former have a median survival of >228 months and the latter 68 months. When the patients are divided into separate classes based on the percentage of carcinoma cells staining for OPN, the five classes show a progressive decrease in survival with increasing percentage of stained carcinoma cells, and this association is also highly significant (P < 0.0001). Other tumor variables that show a significant association with patient survival times in this group of patients include nodal status, tumor size, histological grade, staining for c-erbB-2, estrogen receptor alpha, or p53. Analysis of the association of patients with carcinomas staining for OPN and their survival in subgroups defined by these tumor variables shows that positive staining for OPN in each subgroup is associated with poorer survival. There is little difference in patient survival times in the OPN-negative group of patients with or without any of the other tumor variables examined. Multivariate regression analysis for 202 patients shows that staining for OPN is most highly correlated with patients' deaths (P < 0.0001), but involved lymph nodes (P = 0.0007), fixed tumors (P = 0.0008), and staining for estrogen receptor alpha (P = 0.008) are also significant independent prognostic variables with that for c-erbB-2 being of borderline significance (P = 0.060). These results suggest that in this group of patients, the presence of the metastasis-associated protein OPN is tightly correlated with patient demise.