Cytogenetic studies of bone marrow in breast cancer patients after adjuvant chemotherapy

Acute Myeloblastic Leukemia after Adjuvant Chemotherapy with Melphalan in Breast Cancer. Case Report with Cytogenetic Analysis

Therapy of solid and hematologic tumors with alkylating agents appears to increase the frequency of acute non-lymphocytic leukemia (ANLL), as indicated by the cases reported in the literature. The carcinogenetic mechanism of alkylating agents seems related to their ability to damage DNA, and this is supported by the findings of multiple cytogenetic abnormalities in these patients. We report a case of ANLL secondary to therapy with melphalan, which was utilized on an adjuvant basis for breast cancer. ANLL developed 24 months after chemotherapy was discontinued. Results of the cytogenetic analysis in our patient showed multiple rearrangements and marker chromosomes. Among these was a large metacentric chromosome, identified in 6 of 8 karyotypes, in the size range of group A, which probably resulted from a translocation t(7;14) (7qter→7p11::14p11-→14qter). The natural history of the underlying disease and of the ANLL in our patient and data from chromosomal analysis seem to confirm the hypothesis that alkylating agents are potentially leukemogenic in man, probably through genetic damage. This possibility should be considered when such cytotoxic drugs are used in an adjuvant setting.

Specific chromosomal mutagenesis observed in stimulated lymphocytes from patients with S-ANLL

An analysis of R-banded PHA-stimulated lymphocytes from 13 patients with secondary acute non-lymphocytic leukemia (S-ANLL) following breast cancer or lymphoma, and treatment by alkylating agents and/or radiotherapy, is reported. We found that chromosomes 5, 7, 11 and 17 are over-involved in structural rearrangements. These anomalies are similar to those observed in the same categories of patients without S-ANLL, and after in vitro treatment of normal lymphocytes by the alkylating agent melphalan. These anomalies are thus likely to be induced by treatment, independently of S-ANLL. However, the same chromosomes (5, 7, 11 and 17) are recurrently deficient in leukemic S-ANLL clones. In spite of these similarities, it remains unlikely that the deficiencies observed in leukemic clones were directly induced at the time of treatment. Probably, treatment of primary cancers induces nonrandom mutations of recessive genes located on these chromosomes as also indicated by chromosomal lesions. Various rearrangements including deletions of the homologous normal counterparts may then occur, unmasking mutated recessive genes. The latter stage would be concomitant with the leukemogenic process.

Chromosomal aberrations in lymphocytes of patients treated with melphalan

Chromosome lesions detected in lymphocytes from 14 patients previously treated with melphalan, a bifunctional alkylating agent, have been analyzed on R-banded preparations. In comparison to controls, there was no significant increase of chromatid-type lesions, but chromosome-type lesions were quite frequent, affecting 21.5% of metaphases, on the average. Reciprocal translocations represent 54%, unbalanced translocations 15%, deletions 19% and inversions 6% of all rearrangements. Most of these would not have been detected without the use of chromosome banding. The distributions of affected chromosomes and chromosome bands were not random. Almost all imbalances resulting from rearrangements lead to losses but not to gains. The distribution of the abnormal chromosomes has been compared to that observed in controls and in in vitro experiments, and to the characteristic pattern of malignant cells from patients affected by secondary acute leukemia (ANLL).

The short arm of chromosome 6 is nonrandomly rearranged in secondary myelodysplastic syndromes

Eight patients with a myelodysplastic syndrome showed a structural rearrangement of the short arm of chromosome #6 involving the distal segment 6p22----6pter. In four cases the myelodysplastic disorder appeared after treatment with chemo- and/or radiotherapy. Cytogenetically, the 6p anomaly was consistently associated with abnormalities of chromosome #5 and/or #7 in seven of eight cases. We believe we identified a new site on 6p that is nonrandomly involved in iatrogenically and possibly also environmentally induced malignant hematologic disorders.

An acquired Robertsonian translocation dic(14;14)(p11;p11) in a patient with a myelodysplastic syndrome following treatment of multiple myeloma

Acquired Robertsonian translocations are considered to be very rare chromosome changes in human malignancy, and only three cases have been described. We report a dic(14;14)(p11;p11) in a patient with myelodysplastic syndromes (MDS) following treatment for multiple myeloma. This patient also had other complex chromosomal abnormalities. The pattern of karyotype evolution in this patient was established by a series of cytogenetic studies. The relationship of the complex chromosomal changes to MDS following treatment for multiple myeloma is discussed.

Translocations and deletions with breakpoint on 21q are nonrandomly associated with treatment-related acute nonlymphocytic leukemia and preleukemia

Six of 70 (8.6%) consecutive cases with therapy-related acute nonlymphocytic leukemia (ANLL) or preleukemia had a translocation or deletion with a breakpoint on 21q. Such aberrations were seen in only one of 200 (0.5%) consecutive cases of de novo ANLL examined at our laboratory. The figures reflect a 17.1-fold increased incidence of 21q aberrations in therapy-related ANLL or preleukemia, compared with ANLL de novo. The difference is highly significant (p = 0.003). The increased incidence of 21q aberrations in therapy-related myelodysplastic syndromes was confirmed by literature studies. Band 21q22 was most often involved. Cases with t(8;21), which is strongly associated with the M2 variant of ANLL, or cases with i(21q), which is supposedly due to a centromeric misdivision, were not included in the count. It is concluded that the 21q aberrations are associated with treatment-related ANLL or preleukemia with at least the same degree of specificity as aberrations of #5 and #7.

Preleukemia and leukemia with 12p- and 19q+ chromosome alterations following Alkeran therapy

Among 20 patients with acute nonlymphocytic leukemia or dysmyelopoietic preleukemia secondary to Alkeran therapy for another tumor, four had a del(12)(p11-p12) and four had a translocation to 19q13 among multiple karyotypic alterations in their neoplastic hematopoetic clones. It is suggested that these two cytogenetic abnormalities may occur nonrandomly in such hemic disorders and may play a limited role in their pathogenesis.

Carcinogenicity of antineoplastic agents in man

Review of the literature shows that: Anticancer drugs are in all probability mostly also carcinogenic. Alkylating agents such as melphalan, chlorambucil and cyclophosphamide seem to lead to the highest rate of second malignancies. Second malignancies after antitumour drugs are mostly acute leukaemias. Conditions which could influence the carcinogenicity of an antitumour drug are (a) its carcinogenic potency; (b) long-term administration; (c) the total dose used and (d) long-term survival of the patient. Irradiation and chemotherapy seem to have the greatest carcinogenic potential, e.g. in malignant lymphomas. The role of immunosuppression as a co-carcinogenic factor is difficult to estimate. Although transplant patients on anticancer drugs for immunosuppression have a higher risk of reticulosarcomas, but not of solid tumours, there is no evidence to suppose that in general immunosuppression and carcinogenicity are directly related. There is no reason to abandon intensive chemotherapy regimes if they lead to significant therapeutic results on the grounds of possible carcinogenicity of these drugs.

Adjuvant chemotherapy of breast cancer: hope--reality--hazard?

According to a NIH Consensus-Development Statement, adjuvant polychemotherapy following mastectomy is considered beneficial to premenopausal patients with positive axillary nodes. Nevertheless, the role of adjuvant chemotherapy in relation to menopausal status, axillary lymph node status, estrogen receptor status, choice and dose of agents, and long-term survival is not defined. Based on experimental background information and theoretical deductions, the clinical results have fallen short of expectations. The data of Bonadonna's CMF study reveal that the overall 5-year survival is increased by 4%; premenopausal patients benefit by 12% whereas treated postmenopausal patients have a 5% less chance of survival. Only those patients benefit who can tolerate a "full or nearly full dose"; these are only 17%. At this time it is not clear whether the small survival differences from adjuvant chemotherapy represent a real step forward in the fight against breast cancer. In the majority of patients (75 to 85%), at the time of adjuvant chemotherapy, systemically disseminated cancer cells are at mitotic rest or their proliferation is minimal. At this stage, adjuvant chemotherapy has no or little effect. Therefore, only a small proportion of patients (15 to 25%) has subclinical systemic cancer growth at the time of primary therapy or thereafter; only these patients have a chance to respond to chemotherapy. In view of this tumor kinetic problem and the hazards of chemotherapy, it seems advantageous (a) to focus on definition of patient subgroups at high risk for early recurrence post primary therapy to serve as participants in trials of adjuvant chemotherapy and/or (b) to concentrate on early diagnosis of recurrent disease for immediate institution of endocrine- and/or polychemotherapy.

Hematologic and cytogenetic study of two cases of acute leukemia associated with breast cancer

The authors present two cases of patients with breast cancer with lymph node extension and who both had surgery. As a pancytopenia with hypercellular bone marrow was discovered at the same time in the first patient, she received no complementary treatment; 4 months later, she presented with an acute lymphocytic leukemia (ALL) for which a remission was easily induced, but she died of a pulmonary infection. The second patient received local radiotherapy (50 grays) and adjuvant chemotherapy (Alkeran for 26 months). Forty-seven months after the diagnosis of breast cancer and 16 months after the end of the treatment, an acute nonlymphoblastic leukemia (ANLL; M6) was diagnosed after 8 months of a preleukemic state. Treatment did not produce any results and death occurred on the 17th day. Cytogenetic studies on the bone marrow cells of both patients were performed. In the first patient in the ALL phase normal cells coexisted with a 47 chromosome clone, the extra chromosome being a D (+ 13?). In the second patient, several karyotype abnormalities were already present in the preleukemic state and also during the acute leukemic phase. No normal mitoses were found; hypodiploidy was present as well as major abnormalities such as markers, rings, and, among others, the systematic loss of a #5 and a #7. The first patient seems to have presented with a de novo ALL, associated with the malignant tumor; whereas, the second patient showed all the characteristics of an induced ANLL. The clinical, hematologic, and cytogenetic characteristics of these two patients are analyzed and compared to those of other cases in the literature.

Chromosomes and causation of human cancer and leukemia. L. Cytogenetics of leukemias complicating other diseases

Complicating (secondary) leukemias in 20 patients, 18 of whom had various forms of neoplasia treated with chemotherapy and/or radiation, have been examined in regard to the karyotypic findings present in the leukemic cells of the marrow. In addition, the published cases of complicating leukemia have been tabulated. Based on the results of the present study and those in the literature it appears that chromosomes #3 and #17 should be stressed as being nonrandomly involved in complicating leukemia in addition to the previously stressed chromosomes #5 and #7. The results of the present study are discussed in relation to those reported in the literature, and stress put on the significance of cytogenetic changes in relation to possible causative factors of the complicating leukemia. The hypothesis is advanced that these nonrandom chromosome changes may reflect causative specificity of the complicating leukemia and that a concerted effort must be made to obtain more cogent information on the role of noxious agents in the causation of complicating leukemia.