Chromosome fragility of lymphocytes from breast cancer patients in relation to epidemiologic data

Evaluation of micronuclei frequency in the cultured peripheral blood lymphocytes of cancer patients before and after radiation treatment

The frequency of micronucleated binucleate lymphocyte (MNBNC) was determined in the peripheral blood lymphocytes of patients suffering from various types of cancer before the onset of radiation treatment, middle (mid-) of the treatment and after completion of the treatment (post-treatment). The frequency of micronuclei increased significantly in the pretreatment sample of cancer patients when compared with the normal untreated healthy volunteers. During the middle of the radiotherapy an approximate two or > two-fold increase was observed in the micronuclei frequency in most of the patients when compared with the concurrent pretreatment samples. Immediately after the completion of treatment, the frequency of micronuclei further increased, and this increase was significantly higher than that of pretreatment and mid-treatment samples. Out of 27 patients analyzed, only nine patients did not have any history of smoking, tobacco chewing or alcohol consumption, while the remaining 18 patients had a history of either smoking, tobacco chewing or alcohol consumption or combination of two or all habits at the time of blood collection.

The expression of common fragile sites in peripheral blood lymphocytes of breast and colorectal cancer patients with aphidicolin

The frequency and distribution of aphidicolin induced common fragile sites was evaluated on chromosomes of peripheral blood lymphocytes in 10 breast and 10 colorectal cancer patients, and 10 healthy controls to determine correlation between specific fragile sites and cancer breakpoints. Fifty complete metaphases were screened from each culture and the results were evaluated by Student's t-test. The total number of fragile sites was found as 933 in breast cancer patients, 950 in colorectal cancer patients and 501 in control group. Both the number of aberrations per cell and number of aberrations per damaged cell were significantly higher in the patient groups. These findings indicate that genetic instability in the breast and colorectal cancer patients increased and fragile sites may play a critical role in the pathogenesis of breast and colorectal cancer.

A patient with meningioma showing multiple cytogenetic abnormalities and a constitutional translocation (3;9)(q13.3;q22)

Several different clonal abnormalities in both hypo- and hyperdiploid cell lines were observed in tumor cells of a 35-year-old man with a syncytial meningioma. A translocation involving chromosomes 3 and 9, t(3;9)(q13.3;q22), was present in all analyzable tumor cells and proved to be constitutional. The breakpoints 3q13.3 and 9q22 are involved in acquired karyotypic abnormalities in a number of tumors and might be situated near a tumor suppressor gene. The development of malignancies has been observed in patients with constitutional translocations involving 3q13.3 but not 9q22. We conclude that translocations involving 3q13.3 and maybe 9q22 could present constitutional chromosomal abnormalities predisposing for the development of a malignancy. Patients in whose tumor cells a translocation involving 3q13.3 or 9q22 is observed should be checked for a similar constitutional abnormality.

The expression of aphidicolin-induced fragile sites in familial breast cancer patients

The expression frequency of aphidicolin-induced fragile sites was examined in familial breast cancer patients to determine whether this parameter could be used as a marker of genetic susceptibility in at-risk individuals. No difference was found in expression frequency between the breast cancer patients and a group of normal individuals (p = 0.61). This indicates that the expression frequency of aphidicolin-induced fragile sites is not a suitable marker for assessing genetic susceptibility in familial breast cancer.

Constitutional balanced translocations in patients with solid tumors

In a sample of 329 patients with a solid tumor (colon and breast adenocarcinoma, cervical carcinoma, and meningioma), four balanced constitutional translocations were observed. Two were t(13q14q), and two were reciprocal translocations. Comparison with surveys of newborns showed a significant excess of translocations in our sample.

Chromosome fragility in lymphocytes of women with cervical uterine lesions produced by human papillomavirus

We studied 30 women with cervical lesions that showed human papillomavirus infection (HPV). Cervical HPV infection was diagnosed by cytology, histology, immunohistochemistry, and electron microscopy, as well as by DNA viral hybridization in situ with 6, 11, 16, and 18 HPV types. Three groups of patients were studied: 15 women infected by HPV of 6 and 11 types with koilocytic lesions and benign evolution, 15 women infected by HPV of 16 and 18 types with koilocytic lesions and malignant evolution, and 15 normal women without cervical lesions who served as controls. For each group, chromosome fragility was studied in peripheral blood lymphocytes. Aphidicolin (AP) was used as a clastogenic agent at a concentration of 0.12 microM. There were significant differences (p less than 0.001) between the control population and the patients affected by HPV. There were also significant differences (p less than 0.001) between the two groups infected with HPV. Our findings support the concept that chromosome fragility could serve as a cytogenetic marker to measure evolution, prognosis, and treatment of cervical lesion associated with HPV.

Breast cancer cytogenetics and beyond

It is hypothesized that cancers arise as a result of genetic or chromosomal alteration. Evidence for this is provided by the leukaemias and lymphomas in which cytogenetic studies are of established value in diagnosis, classification and follow-up. In contrast, the cytogenetic study of all solid tumours, including breast carcinoma, is in its infancy. However, cytogenetic studies indicate that clonal structural alterations do occur, affecting several loci on a number of chromosomes. Molecular studies provide further evidence of recurring chromosomal breakpoints in breast cancer. This paper reviews the chromosomal rearrangements observed to date and discusses their relevance to the biology of breast cancer.