A Ph-negative chronic myeloid leukemia patient with a non-classical BCR-ABL rearrangement characterized by fluorescence in situ hybridization.

A patient with chronic myeloid leukemia (CML), a normal karyotype and a BCR-ABL rearrangement is presented. Southern blot analysis detected the rearrangement, whereas RT-PCR with b2a2 and b3a2 primers did not. Fluorescence in situ hybridization (FISH) with an ABL probe (9q34.2) and an Mbcr probe (22q11) showed ABL and BCR signals on chromosome 22. Subsequent FISH studies with cosmids mapping to 9q34.3 showed normal hybridization patterns to chromosome 9, suggesting an interstitial insertion of ABL containing DNA sequences into chromosome 22 in this patient. The lack of reciprocal translocation sequences was investigated with RT-PCR, primers a1b and c7. The absence of ABL-BCR gene expression in this and other patients described in the literature with this subtype of Ph-negative CML, does not seem to have an impact on the clinical course of the disease.

The accumulation of multiple genetic abnormalities in individual tumor cells in human breast cancers: clinical prognostic implications.

PURPOSE: Human solid tumors undergo multiple genetic evolutionary changes as they evolve from the normal state to advanced stages of malignancy. This study characterizes the degree of advancement of primary human breast cancers in their genetic evolutionary pathways, and determines if this is of clinical significance. MATERIALS AND METHODS: Correlated cell-by-cell measurements of cell DNA content, HER-2/neu protein content per cell, and H-ras protein content per cell were obtained by means of multiparameter flow cytometry on primary tumors from 95 patients with clinically localized breast cancer. Laboratory findings were correlated with subsequent clinical course in 91 of these patients. RESULTS: Multiple genetic abnormalities were found to accumulate in individual cells in primary human breast cancers. Almost all tumors contained subsets of cells with one, two, or three abnormalities per cell in various combinations. After a median follow-up time of 32 months, 11 of 13 patients with early recurrence had primary tumors in which more than 5% of cells were hypertetraploid, overexpressed HER-2/neu protein, and overexpressed H-ras protein (triple-positive cells). The duration of disease-free survival among patients with primary tumors that contained triple-positive cells was significantly shorter than for patients whose tumors did not contain triple-positive cells. The presence of subpopulations of cells with maximums of only one abnormality per cell or only two abnormalities per cell, in any combination, was of no prognostic significance. Among patients whose nodal status was known, 12 had recurrent disease, and all had positive axillary nodes. Among 36 patients known to have negative axillary nodes, no recurrence has been reported to date. CONCLUSIONS: The number of genetic abnormalities that accumulate in individual cells in primary breast cancers reflects the degree of advancement of a tumor in its genetic evolutionary sequence, and provides useful clinical prognostic information. Because follow-up duration is still relatively short, and because disease in node-negative patients tends to recur later than in node-positive patients, it is still too early to know if three measurements per cell will be sufficient to improve prognosis in node-negative disease.

Assessing sequential oncogene amplification in human breast cancer.

Studies of amplification and/or overexpression of c-myc, HER-2/neu, and H-ras in breast cancer have shown that each is associated with a poor prognosis. The purpose of this study was to explore the possibility that there is a preferred sequence of amplification of these oncogenes in breast cancer. The frequencies of amplification and patterns of co-amplification of c-myc, HER-2/neu, and H-ras were studied in a group of 84 breast cancers. The data suggested a preferred sequence of amplification that consisted of c-myc amplification-HER-2/neu amplification-H-ras amplification. This model was supported by loglinear analysis. In addition, the levels of amplification of JC-A, a DNA fragment newly isolated from a patient with advanced breast cancer, were studied in 61 of these cases. The data suggested that JC-A amplification occurred early. Loglinear analysis supported a model in which JC-A amplification occurred either before or after c-myc amplification but was unrelated to Her-2/neu or ras amplification.

Preferred genetic evolutionary sequences in human breast cancer: a case study.

Multiparameter flow cytometry studies were performed on the cells of an aggressive human breast cancer at the time of diagnosis and at relapse. The aneuploid cells that overexpressed large amounts of both HER-2/neu and ras survived intensive chemotherapy and were responsible for tumor relapse. At relapse, these cells were shown to overexpress simultaneously at least five oncogenes: HER-2/neu, ras, EGF receptor, p53 and c-myc. A partial reconstruction of the genetic evolutionary sequence in this tumor indicated that HER-2/neu overexpression was an early step in the sequence. Subsequent HER-2/neu overexpression, EGF receptor overexpression and p53 protein overexpression were each associated with ras overexpression. The data suggest that ploidy and oncogene overexpression cannot be used as independent clinical prognostic factors. The ability to characterize tumors according to the degree of advancement in the genetic evolutionary might serve as a basis for genetic staging for adjuvant therapy.