Constitutive heterochromatin (C-banding) studies in patients with testicular malignancies

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.

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).

Constitutive heterochromatin polymorphisms in children with acute lymphoblastic leukemia

The C-band heterochromatin polymorphisms of chromosomes 1, 9, and 16 were studied on peripheral lymphocytes of 67 children with acute lymphoblastic leukemia (ALL) and 50 control individuals. A statistically significant difference between patients and controls was found for large heterochromatin regions (level 3) of chromosomes 1 and 9 (P < 0.001) and for small heterochromatin regions (level 1) of chromosome 16 (P < 0.001). The patients also showed a significant increase in chromosomes 1 and 9 heteromorphism with respect to controls (P < 0.001).

Laterality, maldescent, trauma and other clinical factors in the epidemiology of testis cancer in Victoria, Australia

Clinical factors were studied in a population based survey of 1,116 cases of testicular neoplasms in Victoria, Australia, between 1950 and 1978. The ratio of right to left sided tumours was 54:46, but the left side predominated among sarcomas (P = 0.006), and in older men. The relative risk (RR) for men with unilateral maldescent was 15 (CI 10-23) and for men with bilateral maldescent 33 (CI 20-55) (odds ratio 1.4, CI 0.5-4, P = 0.7). Calculations per testis in men with unilateral maldescent showed an elevated risk for both the maldescended testis (RR 28, CI 19-41, P less than 0.0001) and the normally descended testis (RR 3, CI 1.2-6, P = 0.04). The RR for men with abdominal maldescent was 55 (CI 36-83) compared to 7 (CI 4-11) for those with inguinal maldescent (odds ratio 8, CI 3-20, P less than 0.0001). Seminomas were more common than nonseminomas (NSGCT) in men with a history of maldescent (odds ratio 1.7, CI 1.1-3, P = 0.02) and also among corrected cryptorchids compared to uncorrected (P = 0.005). Seminomas were diagnosed at an earlier median age in men with corrected cryptorchid testes compared to uncorrected (P = 0.03) and in men with corrected cryptorchid testes compared to normally descended (P = 0.001). Maldescent was also associated with hernia (P = 0.04). Twenty-eight per cent of patients recorded a history of trauma with a higher proportion among NSGCT than among seminomas (P = 0.03). Prior malignancies were reported in nine patients, compared to 3.6 expected; prostate cancer (2) and malignant melanoma (2) were the greatest contributors to the excess.

Heteromorphism of chromosome 1, 9 and 16 homologues in high- and medium-longevity level regions

Regional and age-related peculiarities of chromosomal polymorphism are established as a result of studies in C-band heteromorphism of chromosomes 1, 9 and 16 in the long-lived subjects, their relatives and population groups of the Abkhazian and Ukrainian regions. Heteromorphism frequencies of chromosomes 1 and 9 homologues are high in the Abkhazian as compared with the Ukrainian regions. Age-related differences as to the degree of expression of chromosome 9 C-band heteromorphism found are as follows: in the Abkhazian region the frequency of variants with a high degree of heteromorphism increases with age, while in the Ukrainian region, with a low degree of heteromorphism, it decreases.

Variability of Euchromatic and Heterochromatic Regions of Y Chromosome in Two Types of Cancer Patients

Heteromorphism of Y chromosome was studied in head and neck cancer patients and leukemia patients. The results were compared with similar data obtained for healthy men. It was observed that, compared to the controls, mean lengths of Y chromosome were nonsignificantly higher for leukemia patients and lower for head and neck cancer patients. The euchromatic region of Y chromosome (Y-eu) remained comparable in the controls and the leukemia patients, whereas it was smaller in patients with head and neck malignancies. The heterochromatic region (Y-het) was more or less analogous in controls and head and neck cancer patients, however, it was significantly larger in patients with leukemia (P < 0.02).

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.

Heterochromatic variants and their association with neoplasias: V. Non-Hodgkin's lymphomas

A study of heterochromatic regions in chromosomes #1, #9, and #16 was performed on lymphocytes of peripheral blood from 55 normal individuals and 50 patients with non-Hodgkin's lymphoma (NHL). Heteromorphism was present in 90% of the NHL patients, compared with 44% in normal individuals (p less than 0.001). An increase of inv(1), 1qh-, and 9qh-variants was observed in malignant lymphoma patients with respect to controls.

Heterochromatic variants and their association with neoplasias: IV. Colon adenomas and carcinomas

C-band polymorphisms in peripheral blood lymphocytes of 62 patients (33 with colon adenomas and 29 with colon carcinomas) were studied. A significant difference in the frequency of heterochromatic variants in chromosomes #1 in both colon adenoma (56%) and carcinoma (67%) with respect to controls (18%) was observed (p less than 0.001). The heterochromatic variants preferentially involved in both pathologies were inv(1), 1qh-, and inv(9), compared with controls. No differences were found between colon adenomas and carcinomas. We suggest that 1qh- and inv(1) variants are important heterochromatic changes in neoplasia.

Karyotype alterations in human ovarian carcinoma cells during long-term cultivation and nude mouse passage

Cytogenetic analyses of the ovarian carcinoma line EFO-27 demonstrated a limited amount of chromosomal aberrations during long-term maintenance. Between passage 16 and 179 of the cultivation the karyotype shifted to a more homogeneous pattern of tetraploid cells, the occurrence of marker chromosomes mar1 [del(X)] and mar2 [t(X;2)], already present in low-passage cells, was stabilized and marker mar3 [del(9)] was added. After passage through the nude mouse, only near-tetraploid cells were preserved; mar1 to mar3 were abandoned and three additional marker chromosomes mar4 [t(4;9)], mar5 [t(8;9)], and mar6 [t(10;14)] were acquired. Marker 7, consisting of chromosome #16 with an amplified heterochromatic region was characteristically present in nearly all cells and passages of the cultivation. Pericentric variation of the heterochromatin position was found in chromosomes #9 with the exception of nude mouse tumor cells. Hetermorphism of chromosomes #9 and #16 appears to have a prominent role as structural aberration in EFO-27 cells. The results suggest the influence of in vitro and in vivo conditions acting as selection mechanisms concomitant with acquisition or loss of chromosomal markers.

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

To establish the significance of the variability of human chromosome constitutive heterochromatin areas (C-band variants) in a risk of malignancy, C-banding pattern study has been performed in 33 female patients with ovarian or breast adenocarcinoma. The control group included 180 healthy women. The following characteristics of C-bands on chromosomes #1, #9, and #16 were studied: (a) size, (b) size heteromorphisms and (c) inversions, using quantitative and semiquantitative methods of analysis. Our data show no significant difference in the presence of C-band size and location variants in chromosomes #1, #9, and #16 between the patients with adenocarcinoma of the ovary or breast and healthy women. From that we conclude that there is no causal association between the presence of C-band variants on chromosomes #1, #9, and #16 and an elevated risk of ovarian and breast adenocarcinoma.

Heterochromatic variants and their association with neoplasias: III. Multiple myeloma

The incidence of heterochromatic variants was assessed in 26 patients with multiple myeloma (MM) and 55 control individuals. An enhanced frequency of heteromorphism was present in 92% of the MM population compared with 44% of the control group (p less than 0.001). Significant differences with regard to controls were observed in chromosome pairs #1, #9, and #16 due to 1qh-, inv(1),inv(9) and 16qh- variants. We suggest that MM would present an intermediate heterochromatic behavior between hematologic diseases and solid tumors.

Heteromorphism of C-band positive chromosomal regions in CML patients

The heteromorphism of constitutive heterochromatin in chromosomes #1, #9, and #16 was investigated in 44 chronic myelocytic leukemia patients and 44 controls using bone marrow and peripheral blood lymphocyte cultures. A significant increase in the length of C-band region in all the three chromosome pairs as well as a statistically significant difference in the homologs of chromosome #1 was observed in chronic myelocytic leukemia patients when compared with the controls. The frequency of inversions was also greater in the patients than in the controls. A random translocation of 22q was found on either homolog of chromosome #9.

Heterochromatic segment length of Y chromosome in 55 boys with malignant diseases

By investigating heterochromatic segment variability in a group of boys with malignant disease a significantly greater value of the Yc:F index in relation to the control subjects was established.

Constitutive heterochromatin studies in patients with solid tumors

Constitutive heterochromatin of chromosomes 1, 9, and 16 was studied in 101 patients with solid tumors and 85 controls. Lymphocyte cultures were used for performing C-banded chromosome preparations. Two homologous chromosomes were regarded as heteromorphic when there was a 25% difference between their C-band size or when they fell into different classes according to the method of Patil and Lubs (1977). A statistically significant difference between patients and controls was found in chromosome 1 heteromorphism. No statistical difference between patients and controls was found in the heteromorphism of chromosomes 9 and 16. The frequencies with which pericentric inversions of the heterochromatin in chromosomes 1 and 9 occurred in cancer patients were 9.9% and 12.9%, respectively. Patients displaying this type of polymorphism usually showed an increased rate of chromosome associations. The most frequent associations were found between heterochromatic regions of chromosomes 1 and 9 and between the chromosome 9 heterochromatin and D acrocentrics. These results support the hypothesis concerning the involvement of constitutive heterochromatin of chromosome 1 in malignant disease.

Chromosome 1 heterochromatin variants and cancer: a reassessment

Evidence for a relationship between chromosome #1 heterochromatin polymorphisms and cancer has been reviewed. Eighty-four of 135 (62%) patients with epithelial malignancies were heteromorphic for C-band size compared with 38 of 107 (36%) controls (significant at the 0.1% level). However, only 33 of 67 (49%) patients with nonepithelial malignancies were heteromorphic (not significantly different from controls). Similarly, the incidence of partial inversions of the C-band region in one or both homologs was significantly greater than controls [28 of 107 (26%)] for patients with epithelial [66 of 135 (49%)] but not nonepithelial [25 of 67 (37%)] malignancies. However, when the presence of either or both size heteromorphism and inversions were assessed, the incidence was significantly higher in patients with nonepithelial [46 of 67 (69%), including 11 of 11 patients with leukemia or myeloproliferative disorders] as well as epithelial [112 of 135 (83%)] malignancies compared with controls [52 of 107 (49%)]. Forty-seven of the patients did not differ significantly from controls with respect to the incidence of chromosome #1 heteromorphism as revealed by the Giemsa-11 technique. However, 26 patients assessed for their chromosome #1 lateral asymmetry pattern differed significantly from controls, having a higher incidence of compound asymmetry with a large proximal and small distal block and a lower incidence of simple asymmetry.

Constitutional C-band pattern in patients with adenomatosis of the colon and rectum

The pattern of polymorphism in the C-band-positive constitutive heterochromatin of chromosomes #1, #9, and #16 was studied in fibroblasts from 23 unrelated patients with adenomatosis of the colon and rectum and in peripheral lymphocytes from 78 control persons. The parameters of the heterochromatic regions analyzed were relative size, symmetry-asymmetry within homologous chromosome pairs, and frequency of inversions. The polyposis coli patients had a significantly higher frequency (p less than 0.05) of partial and total heterochromatin inversion on chromosome #9 than the control group (37.0% compared with 21.8%). In the other parameters studied, no significant differences were found between patients and controls.

C-band heteromorphism in breast cancer patients

The pattern of heteromorphism in the C-band-positive constitutive heterochromatin of human chromosomes #1, #9, and #16 was studied in peripheral lymphocytes of 54 breast cancer patients and 78 control individuals. The parameters of the heterochromatic regions analyzed were relative size, symmetry-asymmetry within homologous pairs, and prevalence of inversions. Significant differences between the two groups were found in C-band size of chromosomes #1, #9, and #16 and in incidence of inversions on chromosomes #1 and #9. Significant differences were noted between premenopausal and postmenopausal cancer patients in regard to inversions on chromosome #9 and between familial and sporadic patients in regard to C-band size on chromosome #16.

Variability of chromosomes 1, 9, and 16 in children with malignant diseases

Heterochromatic segments of chromosomes #1, #9, and #16 were analyzed in 38 children with malignant disease and 42 healthy persons. The analysis was carried out on C-banded metaphases obtained by peripheral blood culture. Using a quantitative method of analysis, an association was established between C-segment length of chromosome #9 and malignant disease in children. A disturbed quantitative relation of C-heterochromatin of chromosomes #1, #9, and #16 was also found in the group of children with malignant disease.

C-banding studies in lymphocytes from patients with tumors of the nervous system

C-banding studies were performed on cultured peripheral blood lymphocytes from 100 patients with tumors of the nervous system and 30 controls. The classification of Patil and Lubs and the heterochromatic index (HI) of Neeley were used to evaluate the heteromorphism. No overall significant differences were found in the frequency of C-band variants when the findings in both tumoral populations and controls were compared, but we did find an excess of 9qh inversions in some groups of tumor patients. An increase in the amount of heterochromatin in patients with pituitary adenomas and high malignancy grade astrocytomas was noted.

Heterochromatic variants and their association with neoplasias. I. Chronic and acute leukemia

C-banding studies of the heteromorphism of chromosomes #1, #9, and #16 were performed in 120 leukemic patients: 56 with chronic myelocytic leukemia (CML), 45 with acute lymphoblastic leukemia (ALL), and 19 with acute nonlymphoblastic leukemia (ANLL). No differences were found among patients and controls with regard to sex. Our data showed a significant increase of polymorphism in chromosome #1 in the three neoplastic groups; the heterochromatic variant preferentially involved 1qh-, whereas there were no significant differences in heteromorphism in chromosomes #9 and #16.

Variability of euchromatic and heterochromatic segment of the Y chromosome in men with malignant tumors and in a control group

In this study, Y chromosome variability was analyzed in 58 male patients with malignant tumors and 55 healthy male controls. No difference in the size of Y chromosome was established between the two groups studied, but a statistically significant difference in the length of euchromatic and heterochromatic segments was found. A significantly greater length of heterochromatic segments was established in the patients compared with the control group (p less than 0.02). The length of the euchromatic segment was shorter in the patients than in the controls (p less than 0.02).

C heterochromatin variation in couples with recurrent early abortions

The possible influence of the high polymorphic C heterochromatic regions of human chromosomes 1, 9, 16, and Y on meiotic chromosome segregation was investigated. Faulty chromosome segregation may be the result of either an abnormal quantity of C heterochromatin on the homologues, or disequilibrium between the homologues. The aim of our study was to determine whether either a variation in the amounts of total C heterochromatin or differences in the amounts of C heterochromatin between homologues could lead to faulty chromosome segregation. The study was performed on C banded metaphases obtained from peripheral lymphocyte cultures of 15 couples with recurrent early abortions and 15 control couples, all Caucasians. Analysis of variance was first performed on separate metaphases to measure intra-individual, inter-individual, and between population variation in a hierarchical model. Since the significant intra-individual differences covered the other parameters we performed, secondly, a one way analysis of variance on the mean values of metaphases per person in order to measure the inter-individual and between population variation. The results did not show a relationship between C heterochromatin lengths and occurrence of recurrent abortions.

C-band pattern in lymphocytes of patients with soft tissue sarcomas

The pattern of heteromorphisms in the C-band-positive constitutive heterochromatin of human chromosomes No. 1, 9, and 16 was studied in peripheral lymphocytes of 45 patients with soft tissue sarcomas and 78 control individuals. The parameters of the heterochromatic regions analyzed were relative size, symmetry-asymmetry within homologous pairs, and incidence of inversions. No consistent differences were found in these parameters between controls and sarcoma patients.