Identification of a new subset of cells exhibiting dendritic phenotypes in patients affected by breast proliferative disorders.

We report that a subset of circulating cells reacting with a monoclonal antibody raised against a protein marker is significantly increased in the peripheral blood of women carrying benign or malignant breast diseases, particularly in patients under 55 years of age with ductal mammary carcinomas. These cells were statistically (confidence level of 99%) less represented in a control population including healthy women or women carrying carcinomas of origin other than breast. Double staining analysis showed that they harbor markers of dendritic cells and exhibit endo- cytic activity, as determined by their ability to internalize FITC-dextran particles. Their dendritic morphology was further demonstrated by electron microscopy of sorted antibody-positive cells. However, expression of surface molecules, such as CD34 and CD14, usually not present in differentiated populations of dendritic cells was also observed. Adherent cells of patients with breast ductal carcinoma including mostly cells of this new subset were efficient stimulators of mixed lymphocyte reaction, attaining maximal stimulatory activity attained after TNFalpha treatment. In conclusion, we have shown that a subset of cells characterized by a phenotype suggestive of a yet undescribed stage of maturation of the dendritic cell lineage is accumulated in the blood of patients affected by breast proliferative disorders.

Circulating antibodies against the breast tumor marker GCDFP-15/gp17 in mammary carcinoma patients and in patients carrying benign breast conditions.

Sera samples from 111 women, including 73 breast cancer patients and 38 patients with benign diseases of the breast, were examined. These were compared with samples from healthy women or from patients carrying tumors of origin other than breast as controls. This was done to determine whether antibodies against GCDFP-15/gp17, a protein of gross cystic disease fluid also secreted by mammary apocrine tumor cells, could be found. We observed that 2.6% of mammary disease patients affected by benign conditions and 5.5% of patients carrying malignant mammary gland tumors expressed statistically significant amounts of antibodies against GCDFP-15/gp17 (p < 0.01). The highest circulating anti-GCDFP-15/gp17 antibody levels occurred in patients with highly malignant ductal or lobular carcinoma of the breast and in patients with dysplasia. No correlation was found between the presence of circulating antibodies and the size of the tumor or the age of the patients. A bimodal correlation with the percent of invaded lymph nodes was observed instead. IgM and IgG isotypes were detected among the circulating anti-GCDFP-15/gp17 antibodies, suggesting the involvement of a T-cell-mediated immunoresponse. Our findings raise the possibility that the anti-GCDFP-15/gp17 immune response may be useful as a tool for investigating some aspects of the mechanisms of breast disease progression and that GCDFP-15/gp17 may be explored as an antigen for anti-tumor vaccination. Int. J. Cancer (Pred. Oncol.) 84:568-572, 1999.

Reversion of a transcriptionally defective MHC class II-negative human B-cell mutant.

RJ2.2.5, a mutant derived from the human B-lymphoma cell, Raji, is unable to express the MHC class II genes because of a recessive transcriptional defect attributed to the lack of an activator function. We report the isolation of a RJ2.2.5 revertant, namely AR, in which the expression of the mRNAs encoded by these genes is restored. Comparison of the binding of nuclear extracts or of partially purified nuclear preparations from the wild-type, the mutant and the revertant cells to a conserved MHC class II promoter element, the X-box, showed no alteration in the mobility of the complexes thus formed. However, in extracts from RJ2.2.5, and other MHC class II negative cell lines, such as HeLa, the amount of complex observed was significantly higher than in wild-type Raji cells. Furthermore, the binding activity exhibited by the AR revertant was lower than that of the RJ2.2.5 and higher than that of Raji. The use of specific monoclonal antibodies indicated that in all cases c-Jun and c-Fos or antigenically related proteins were required for binding. An inverse correlation between the level of DNA-protein complex formed and the level of MHC class II gene mRNA expressed in the three cell lines was apparent, suggesting that overexpression of a DNA binding factor forming complexes with class II promoter elements may cause repression of MHC class II transcription. A model which reconciles the previously ascertained recessivity of the phenotype of the mutation carried by RJ2.2.5 with the findings reported here is discussed.