C-band polymorphisms in lymphocytes of patients with ovarian or breast adenocarcinoma

Heterochromatin variants in 109 ovarian cancer patients and 192 healthy subjects

Aberrations of the C-band region of chromosome no. 1 (1qh) were studied in 109 patients with ovarian cancer and 192 healthy subjects. The groups were compared for heterochromatin size variations, intrapair size asymmetry, and inversion. No significant correlation was found between the size of 1qh and ovarian cancer. Heterochromatin size asymmetry was estimated visually and determined by objective measurement of 1qh length or area; the methods show strong correlation. The measurements were normalised by comparison with the length or area of 16p or the entire chromosome no. 1. However, since good reliability was found by simply relating the 1qh size difference to the mean 1qh size, this was considered an appropriate and simpler method of normalisation. Asymmetry indices of length and area measurements correlated well, implying that the simpler method of length measurements can be readily used. 1qh asymmetry, measured objectively or estimated visually, was significantly increased in the cancer patient group. The incidence of C-band inversion was significantly increased in the patient group. Moreover, inversion increased significantly with increasing 1qh asymmetry.

Familial occurrence of cancer and heteromorphism of the heterochromatic segment of chromosome 1

During the last decade, evidence has been forthcoming in support of the correlation between heteromorphism of human chromosome 1qh and the incidence of various malignancies in the carriers of such heteromorphism. We present data from a family with hereditary predisposition to cancer. In this family, five members in a sibship of seven developed ovary and/or colon carcinoma at comparatively young ages. A further 4 cases of malignant disease were ascertained, when a pedigree of 36 family members of 3 generations was constructed. Chromosome analysis was carried out in G- and C-banding from peripheral blood cultures of 19 family members. Distinct heteromorphism in the chromosome 1qh region was detected in 15 (79%) of them, including all 3 cancer patients investigated.

Constitutional C-band polymorphism in lymphocytes from patients with chronic myeloid leukemia

The C-band heterochromatin polymorphism of chromosomes 1, 9, and 16 was studied in lymphocytes from 53 patients with Ph1-positive chronic myeloid leukemia (CML) and 183 control persons. The patients had significantly larger heterochromatic blocks on chromosome 16 (p less than 0.01) and fewer partial inversions of chromosome 9 (p less than 0.05) than the control persons, whereas no differences were found for the symmetry/asymmetry pattern. We suggest that the increased constitutive heterochromatin regions may, via sister chromosome exchange, facilitate homo- or hemizygotization of genes which favor neoplasia development and/or progression.

Hodgkin's disease developing after spontaneous remission of chronic lymphocytic leukemia

We present a 71-year-old patient with chronic lymphocytic leukemia diagnosed 27 years ago. Initially, the disease was staged as Rai II and the patient suffered from secondary immunoglobulin deficiency. Nevertheless, no treatment was necessary at that time. Because of disease progression a single course of chemotherapy was given in 1984. During the following year there was a constant decline of the WBC, accompanied by normalization of the immunoglobulins; both have remained stable ever since that time. However, there was still residual bone marrow infiltration, indicating persisting CLL. In 1993 cervical lymphadenopathy occurred with acute onset. A diagnostic lymphadenectomy revealed Hodgkin's disease of the nodular-sclerosing subtype. The patient was staged as II-III according to the Ann Arbor Classification and underwent radiation therapy. Cytogenetic examination of the bone marrow revealed a normal karyotype with an inversion of chromosome 9. This case demonstrates the rate coincidence of two lymphoproliferative disorders in the same patient. The clinical course and the immunologic findings of this patient are presented, together with a review of the literature.

Expression of aphidicolin-induced fragile sites in lymphocytes of patients with breast cancer

The expression of fragile sites induced by aphidicolin (APC) was evaluated on metaphase chromosomes obtained from the peripheral blood lymphocytes of 26 women with breast cancer and 15 sex- and age-matched normal controls. Both the proportion of damaged cells (P < 0.001) and the mean number of gaps and breaks per cell (0.02 < P < 0.05) were significantly higher in the patient group. There were no differences in either the age-related fragile site levels or the expression of single fragile sites between patients and controls. Our findings indicate an increased genetic instability in women with breast carcinoma.

Cytogenetic findings in 111 ovarian cancer patients: therapy-related chromosome aberrations and heterochromatic variants

The chromosomes of 111 ovarian cancer patients were studied in G- and C-banded slides from peripheral blood lymphocyte (PBL) cultures for chromosome damage caused by chemotherapy and radiotherapy and for asymmetry of the constitutive heterochromatin of chromosomes 1, 9, and 16. We also monitored the survival of these patients to determine whether any secondary neoplasia induced by the therapy and report the findings of our investigations. Melphalan (MEL) was the only drug used in single-drug chemotherapy. The incidence of chromosome abnormalities in melphalan-treated cells (25%) was higher than in the control group (17%). The incidence of structural changes was also higher (10.5%) in the MEL-treated group than in controls (6%). After treatments with combinations of drugs, the incidence of structural changes remained at the same level (11%). In the patients receiving combined treatment with MEL and radiation, the rate of structural changes increased dramatically (24%). The overall rate of chromosome aberrations in this group was also higher (50%). Combination of two or more drugs and radiation produced only 14% structural chromosome changes. The overall rate of chromosome aberrations was also low (20%) in this group. Of 111 patients studied, only 33 were alive 6 years after initiation of the study. Of the surviving patients, eight had rearranged chromosomes in the first analysis. After 5 years, new blood samples were collected from these patients and chromosome analyses showed abnormal karyotypes in all eight patients. All chromosome abnormalities in the second analysis were completely unrelated to those in the first analysis, however. Whether the chromosome changes in the second analysis were due to therapy or to other unknown factors could not be determined. Data on C-banding and the distribution of inversions indicated that 91% of the patients had C-band heteromorphisms of chromosomes 1, 91% had heteromorphisms of chromosome 9, and 69% had heteromorphisms of chromosome 16. Furthermore, inversions were observed in chromosome 1 (41% of patients), chromosome 9 (28% of patients), and chromosome 16 (5% of patients).

Variations in centromeric heterochromatin among patients with pre-malignant and malignant oral diseases

Polymorphism of heterochromatic regions of chromosomes 1, 9 and 16 was studied in 60 oral cancer patients, in 40 patients with oral submucous fibrosis (OSMF) and in 60 normal healthy subjects. The size heteromorphism was significantly greater (p less than 0.001) in chromosome I of the patients. Localization variants were also significantly more frequent among the patients (p less than 0.05 for OSMF and less than 0.001 for oral cancer patients). The C-band heteromorphism patterns remained comparable in OSMF and in oral cancer patients, with chromosome I being the most frequently involved. On correlating the tobacco/areca-nut chewing habit with the presence of C-band heteromorphism, we observed that C-band heteromorphism was present in 89% of the habit-free oral cancer patients and 80% of the OSMF patients with relatively shorter exposure to this habit, i.e. less than 5 years. This signifies that genetic factors are important in the causation of oral precancerous and cancerous conditions and that polymorphism of the heterochromatic regions does appear to play a role in these conditions.

Constitutive heterochromatin C-band polymorphism in prostatic cancer

The size of the heterochromatin C-bands on chromosomes has been reported to be associated with some, but by no means all, human malignancies. No studies along these lines have been performed in prostatic cancer. We therefore investigated the size, incidence of inversions, and symmetry versus asymmetry of C-band heteromorphisms on chromosomes 1, 9, and 16 in peripheral blood lymphocytes from 52 prostatic cancer patients and 183 healthy individuals. There were no differences in C-band heteromorphism on chromosomes 1, 9, and 16 between the patients and the controls. Neither were there any differences when patients with early-stage disease were compared with patients with more advanced cancer. Younger (aged less than 70 years) cancer patients had significantly higher frequencies of larger C-bands on chromosomes 1 (p less than 0.01) and 16 (p less than 0.001) than did patients aged more than 70 years at diagnosis. This could indicate a possible relationship between the amount of constitutive heterochromatin on chromosomes 1 and 16 and susceptibility to early development of prostatic cancer but could also result from the age differences between the two patient groups.

Familial susceptibility to breast cancer: a complex inheritance

The main results of segregation analysis aimed at identifying a major genetic factor involved in susceptibility to breast cancer are reviewed. They show that the existence of a single major gene is not sufficient to explain the distribution of the disease observed in the families concerned and suggest that the genetic inheritance involved is heterogeneous and complex. Heterogeneity has been explored in various studies according to epidemiological criteria. From these analyses, genetically homogeneous subgroups emerged (for instance families with breast cancer only or with affected males). The study of such homogeneous subgroups might help to better locate the susceptibility gene(s) on the chromosome map by analysis of genetic linkage using different markers. The results of segregation analysis depend on how epidemiological factors are taken into account. It is of major importance that epidemiological data on the proband (i.e., the individual prompting selection of a family) as well as on the members of his/her family are taken into consideration to improve understanding of the complexity of breast cancer transmission.

Densitometric measurements of C bands of chromosomes 1, 9, 16, and Y in leukemic and preleukemic disorders

Fifty-six patients with blood disorders (23 with chronic myeloid leukemia, 14 with acute myeloblastic leukemia, seven with acute lymphoblastic leukemia, one with chronic lymphocytic leukemia, and 11 with preleukemia states) were studied. A quantitative and objective method of C band length analysis with well-matched controls was used. The C bands of chromosome pairs 1, 9, and 16 presented a normal distribution that was similar in patients and controls, whereas the Y chromosome presented an abnormal distribution. Smaller C bands in 1qh and higher indexes of intrapair heteromorphism in pairs 1 and 9 were detected in the CML group; the group of acute leukemias (myeloblastic and lymphoblastic) presented a smaller index only in pair 1qh. No other differences in length, heteromorphism, inversion frequency, or sex were detected.

Solid tumor cytogenetics. Progress since 1979

Some of the advances in the past decade in the field of solid tumor cytogenetics are described, with particular reference to nonrandom structural chromosome changes. Although it had been known for many years that meningiomas and salivary gland tumors were associated with changes involving particular chromosomes, it has only quite recently become clear, following the application of suitable culture techniques, that other benign tumors such as lipomas and leiomyomas may also be characterized by specific changes, particularly reciprocal translocations. Reciprocal translocations may also be found in malignant soft-tissue tumors such as liposarcomas (involving 12q as in lipomas) and Ewing's sarcoma. In contrast, the common forms of carcinoma present a more variable picture, although certain chromosomes may undergo nonrandom changes of various types, including translocations, which, however, are generally nonreciprocal. Some of these chromosomes may be quite specific (e.g., chromosome 10 in prostatic and #18 in colorectal cancer), while others appear to be common to many or all types of carcinoma, such as chromosomes 1, 3, 11, and 17, and a small metacentric that may be an i(5p). In carcinoma of the bladder, different chromosome changes may characterize subsets of the tumors. In carcinoma of the cervix, however, the commonly involved chromosomes, 1, 3, ?5, 11, and 17, appear in markers in any combination and are thus not mutually exclusive. Although further study of the chromosome changes in carcinomas is essential to an understanding of their relationship to the molecular changes that are associated with malignant transformation, it can be hypothesized that, while some of the changes result in the duplication of particular genes, e.g., on chromosome 1q, a more important role may be to bring about the loss of chromosomal segments containing tumor-suppressor genes. Evidence from molecular studies that has recently been accumulating for the loss of alleles on, for instance, 3p, 11p, and 17p, which could in part be due to gross chromosomal rearrangements, also strongly suggests the importance of genic loss in malignant transformation. In carcinomas, at least, the changes probably involve a number of genes, each change representing one of the several steps necessary for tumorigenesis.