Molecular genetics and cytogenetics of breast carcinomas: comparison of the two methods.

Molecular genetics and cytogenetics are two different approaches to studying genetic changes in breast carcinoma. We have used karyotype analysis, fluorescence in situ hybridization, and molecular analysis of allelic imbalance on chromosomes 7q and 16q and on both arms of chromosome 17, to study 85 breast carcinomas. Twenty-five of these samples gave results that could be used to compare the two methods. Sixty-nine chromosome arms were compared, of which 48 (70%) gave concordant molecular and cytogenetical results. Samples were processed for karyotyping both by harvesting directly from the fresh tissue and after selective culture for a few days. Karyotypes among the direct harvest samples matched significantly better with the molecular genetics results than karyotypes among the cultured cell preparations.

Instability of chromosomes 1, 3, 16, and 17 in primary breast carcinomas inferred by fluorescence in situ hybridization.

Abnormalities of chromosomes 1, 3, 16, and 17 were examined in 203 metaphase cells from 12 cases of primary breast carcinoma using fluorescence in situ hybridization with chromosome painting probes. The most common structural abnormalities were chromosomal rearrangements, especially translocations, and chromosome 17 was most frequently involved in these types of changes. Chromosome 16 was preferentially involved in the losses and deletions, while chromosomes 1 and 17 were more involved in the gains, including amplifications, than other chromosomes. This approach has revealed a different profile of abnormalities from those normally shown by G-banding analysis. Some of these changes are likely to be novel and may be biologic or clinical importance in breast cancer.

Effects of lymphocytes and fibroblasts on the growth of human mammary carcinoma cells studied in short-term primary cultures.

Breast carcinomas commonly contain varying amounts of fibrous stroma and infiltrates of lymphoid cells. Dickson and Lippman (Endocrine Rev., 8,29, 1987) have proposed a model of growth regulation in breast cancer involving interactions between stroma and carcinoma cells. This model is based on results obtained with established cell lines. In an effort to bring experimentation closer to the clinical situation we have used short-term primary cultures from human breast cancer in co-cultures with lymphocytes and fibroblasts. Cultures were established in a chemically defined serum-free medium (CDM3). Cell types were characterized on the basis of live morphology and expression of vimentin and keratin 18. A semi-quantitative system was developed for measuring growth of epithelial cells, thus defining two indices: maximal growth index (GI-max) and growth rate (GR). Moderate-to-good growth was obtained from 34 out of 46 carcinoma samples (74%) and 30 out of 38 parallel samples of non-cancerous tissue (79%). Success in culture was negatively correlated with the amount of hard stroma but unrelated to age of patient or clinical status. Malignant epithelium was clearly identified in 12 out of 34 (35%) carcinoma samples. For the evaluation of responses of epithelial cells in co-cultures, the cultures from each sample were ranked according to GI-max.(ABSTRACT TRUNCATED AT 250 WORDS)

Interactions between the immune system and breast cancer.

The functional and prognostic significance of lymphocytic infiltration of breast carcinomas has remained unclear. Using primary cultures we have demonstrated that lymphocytes could stimulate the growth of breast cancer epithelium in about half of the cases tested. The growth stimulation was subsequently shown to be strongly correlated with expression of MHC class I by the tumour cells. Furthermore, preliminary data suggest that carcinomas with a mixed population of MHC class I-positive and -negative cells were associated with a higher incidence of lymph node metastases and increased relapse rate compared with tumours that were homogeneously MHC class I-positive or -negative. The interactions between breast cancer and the immune system are clearly complex and the results suggest that the nature of these interactions can be some extent be determined by the level and pattern of MHC class I expression by the tumour cells.

A family showing apparent X linked inheritance of both anencephaly and spina bifida.

A family is reported which includes five males, two with spina bifida, two sibs with anencephaly, and one with both high and low spinal lesions. The affected subjects came from four sibships in three generations. The mode of inheritance of these neural tube defects is consistent with X linkage.

A comparison of cytogenetic studies and flow cytometry in breast carcinomas.

In this study, we compared genetic instability in 70 breast carcinomas analyzed by two different methods, cytogenetics and flow cytometry. This comparison showed that each method has its strengths and weaknesses. Flow cytometry detected aneuploidy in 60% of cases, but missed most of the cytogenetically near-diploid clones and clones with simple chromosomal changes. Cytogenetics revealed chromosomal abnormalities in 50% of the samples. Simple chromosomal changes and multiploidy were readily detected by this method, but some of the clones with a high DNA index by flow cytometry were missed. The two methods gave corresponding results in the majority of cases (54%). In 17 cases, both methods detected matching abnormal clones (r = 0.93) but the DNA index was higher than predicted by the chromosome numbers. Most of the discrepancies might be explained by tumor heterogeneity and insufficient numbers of cells available for cytogenetic analyses. In seven cases, single-cell abnormalities were found that corresponded to a flow cytometry peak. Multiclonality was present in 25% of aneuploid tumors. No association was found between metaphases in cytogenetic preparations and increased S-phase fraction of the tumors, but aneuploid tumors had a significantly higher proliferation rate. Pooling data from both methods demonstrated that the majority of our samples were aneuploid (74%).

Cytogenetic studies of breast carcinomas: different karyotypic profiles detected by direct harvesting and short-term culture.

Chromosome analysis was performed on samples from 85 consecutive patients with breast cancer by one or more of three different methods: direct harvest, culture after mechanical disaggregation, and culture after collagenase digestion. Metaphases suitable for karyotyping were obtained in 70% of the cases; direct harvest yielded metaphases in 29% and cultures without and with digestion in 40% and 59%, respectively. Chromosomal abnormalities were detected in 37 cases. Cells judged to be phenotypically abnormal in culture were twice as likely to reveal chromosomal aberrations as normal-looking cells. Eight cases showed multiclonal abnormalities. Significant differences were detected in the karyotypic profile depending on the method used. With direct harvest, the yield of complex chromosomal changes was 87%, compared to 44% after culture of digested tissue (P < 0.01), and also polyploidy was more common in direct-harvested samples. Detailed karyotypic analysis was possible in 29 primary tumors. The chromosomes most frequently involved were 1, 3, 7, 11, 16, and 17. Recurrent structural abnormalities were der(1;16)(q10;p10), i(1)(q10), del(6)(q21), and del(1)(p22). Breakpoints clustered to the centromere regions of chromosomes 1, 3, 11, 15, and 16 and to the short arms of chromosomes 7, 17, and 19. Seven of twenty-nine fully analyzed cases had a family history of breast cancer, and changes of chromosomes 1, 3, and 15 seemed to be more common in these cases. There was an association between karyotype and survival: The 3 year survival was 63% in patients with complex karyotypic changes and 92% in those without complex changes.

Hereditary cystatin C (gamma-trace) amyloid angiopathy of the CNS causing cerebral hemorrhage.

Hereditary CNS amyloid angiopathy occurring in Icelanders is the first human disorder known to be caused by deposition of cystatin C amyloid fibrils in the walls of the brain arteries leading to single or or multiple strokes with fatal outcome. One or more affected members have been verified by histological examination in 8 families containing 127 affected. These originated from the same geographic area. Abnormally low value of cystatin C found in the cerebrospinal fluid of those affected can be used to support or make diagnosis of this disease, also in asymptomatic relatives. By amino acid sequence analysis the amyloid fibrils in the patients are found to be a variant of cystatin C (gamma-trace), a major cysteine proteinase inhibitor. The variant protein has an amino acid substitution (glutamine for leucine) at position 58 in the amyloid molecule. It is postulated that a point mutation has occurred leading to production of amyloidogenic protein causing the disorder.