Population-based study of cancer among carriers of a constitutional structural chromosomal rearrangement

Mortality and Cancer Incidence in Carriers of Balanced Robertsonian Translocations: A National Cohort Study

A balanced robertsonian translocation (rob) results from fusion of 2 acrocentric chromosomes. Carriers are phenotypically normal and are often diagnosed because of recurrent miscarriages, infertility, or aneuploid offspring. Mortality and site-specific cancer risks in carriers have not been prospectively investigated. We followed 1,987 carriers diagnosed in Great Britain for deaths and cancer risk, over an average of 24.1 years. Standardized mortality and incidence ratios were calculated comparing the number of observed events against population rates. Overall mortality was higher for carriers diagnosed before age 15 years (standardized mortality ratio (SMR) = 2.00, 95% confidence interval (CI): 1.09, 3.35), similar for those diagnosed aged 15–44 years (SMR = 1.06, 95% CI: 0.86–1.28), and lower for those diagnosed aged 45–84 years (SMR = 0.81, 95% CI: 0.68, 0.95). Cancer incidence was higher for non-Hodgkin lymphoma (standardized incidence ratio (SIR) = 1.90, 95% CI: 1.01, 3.24) and childhood leukemia (SIR = 14.5, 95% CI: 1.75, 52.2), the latter particularly in rob(15;21) carriers (SIR = 447.8, 95% CI: 11.3, 2,495). Rob(13;14) carriers had a higher breast cancer risk (SIR = 1.58, 95% CI: 1.12, 2.15). Mortality risks relative to the population in diagnosed carriers depend on age at cytogenetic diagnosis, possibly reflecting age-specific cytogenetic referral reasons. Carriers might be at greater risk of childhood leukemia and non-Hodgkin lymphoma and those diagnosed with rob(13;14) of breast cancer.

Mortality and cancer incidence in carriers of constitutional t(11;22)(q23;q11) translocations: A prospective study

The constitutional t(11;22)(q23;q11) translocation is the only recurrent non‐Robertsonian translocation known in humans. Carriers are phenotypically normal and are usually referred for cytogenetic testing because of multiple miscarriages, infertility, or having aneuploidy in offspring. A breast cancer predisposition has been suggested, but previous studies have been small and had methodological shortcomings. We therefore conducted a long‐term prospective study of cancer and mortality risk in carriers. We followed 65 male and 101 female carriers of t(11;22)(q23;q11) diagnosed in cytogenetic laboratories in Britain during 1976–2005 for cancer and deaths for an average of 21.4 years per subject. Standardised mortality (SMR) and incidence (SIR) ratios were calculated comparing the numbers of observed events with those expected from national age‐, sex‐, country‐ and calendar‐period‐specific population rates. Cancer incidence was borderline significantly raised for cancer overall (SIR = 1.56, 95% CI: 0.98–2.36, n = 22), and significantly raised for invasive breast cancer (SIR = 2.74, 95% CI: 1.18–5.40, n = 8) and in situ breast cancer (SIR = 13.0, 95% CI: 3.55–33.4, n = 4). Breast cancer risks were particularly increased at ages <50 (SIR = 4.37, 95% CI: 1.42–10.2 for invasive, SIR = 22.8, 95% CI: 2.76–82.5 for in situ). Mortality was borderline significantly raised for breast cancer (SMR = 4.82, 95% CI: 0.99–14.1) but not significantly raised for other cancers or causes. Individuals diagnosed with t(11;22)(q23;q11) appear to be at several‐fold increased breast cancer risk, with the greatest risks at premenopausal ages. Further research is required to understand the genetic mechanism involving 11q23 and 22q11 and there may be a need for enhanced breast cancer surveillance among female carriers.

What's new?

The constitutional translocation between chromosome bands 11q23 and 22q11 is recurrent in human populations, with highly consistent breakpoints. A breast cancer predisposition among carriers has been suggested, but previous studies have been small and had methodological shortcomings. In this first long‐term follow‐up study of site‐specific cancer and mortality risks among carriers, an increased risk of breast cancer was observed compared to the general population, with greatest risks in younger women. The results suggest that carriers of t(11;22)(q23;q11) may require enhanced surveillance for breast cancer and point to the importance of the chromosomal regions 11q23 and 22q11 in breast cancer development.

Treatment-related toxicities in children with acute lymphoblastic leukaemia predisposition syndromes

Although most children with acute lymphoblastic leukaemia (ALL) do not harbor germline mutations that strongly predispose them to development of this malignancy, large syndrome registries and detailed mapping of exomes or whole genomes of familial leukaemia kindreds have revealed that 3-5% of all childhood ALL cases are due to such germline mutations, but the figure may be higher. Most of these syndromes are primarily characterized by their non-malignant phenotype, whereas ALL may be the dominating or even only striking manifestation of the syndrome in some families. Identification of such ALL patients is important in order to adjust therapy and offer genetic counseling and cancer surveillance to mutation carriers in the family. In the coming years large genomic screening projects are expected to reveal further hitherto unrecognised familial ALL syndromes. The treatment of ALL cases harboring cancer predisposing mutations can be challenging for both the physician and the patient due to their preexisting symptoms, their reduced tolerance to radio- and/or chemotherapy with enhanced risk of life-threatening organ toxicities, and the paucity of data from ALL patients with the same or similar syndromes being treated by contemporary protocols. Recent studies clearly indicate that many of these patients stand a good chance of cure, and that they should be offered chemotherapy with the intention to cure. Some of these syndromes are characterized by reduced tolerance to radiotherapy and/or specific anticancer agents, while others are not. This review summarises our current knowledge on the risk of acute toxicities for these ALL patients and provides guidance for treatment adjustments.

Constitutional inv(3) in myelodysplastic syndromes

The constitutional pericentric inversion on chromosome 3, inv(3), is rarely found in a normal population. The aim of our study was to investigate its possible link to hematologic malignancy. Chromosomes from bone marrow cells in 890 patients with hematologic disorders were analyzed with the Q-banding technique. Thirty-four patients had inv(3) (3.8%). In 241 patients with myelodysplastic syndromes the frequency was 6.2% as opposed to 2.9% in the remaining 649 patients (p=0.02). The increased frequency of inv(3) in patients with myelodysplastic syndromes indicates that inv(3) could be a risk factor for the development of the disease.

Autoimmune diseases in women with Turner's syndrome

OBJECTIVE

In terms of number of X chromosomes, women with Turner's syndrome cytogenetically resemble men. An increased risk of autoimmune diseases has been observed among women with Turner's syndrome. This study was undertaken to investigate whether the autoimmune disease profile in women with Turner's syndrome is characterized by diseases with a female or male predominance.

METHODS

Using the Danish Cytogenetic Central Register, the Danish National Patient Register, and the Danish Civil Registration System, we estimated relative risk of 46 different autoimmune diseases in a cohort of 798 Danish women with Turner's syndrome followed up for 12,461 person-years between 1980 and 2004. Standardized incidence ratios (SIRs) of first hospitalization for autoimmune disease and 95% confidence intervals (95% CIs) were used as measures of relative risk.

RESULTS

The overall risk of autoimmune disease among women with Turner's syndrome was twice that among Danish women in general (SIR 2.1 [95% CI 1.6-2.7]). For autoimmune diseases with a female predominance, the SIR among women with Turner's syndrome was 1.7 (95% CI 1.2-2.4), whereas the SIR for autoimmune diseases with a male predominance among these women was 3.9 (95% CI 2.5-5.8). Associations were strongest for Hashimoto thyroiditis (SIR 14.6 [95% CI 6.7-27.1]), a strongly female-predominant condition, and type 1 diabetes mellitus (SIR 4.1 [95% CI 2.5-6.3]).

CONCLUSION

Women with Turner's syndrome are at excess risk of autoimmune diseases, notably autoimmune diseases characterized by male predominance.

Is there an association with constitutional structural chromosomal abnormalities and hematologic neoplastic process? A short review

The occasional observation of constitutional chromosomal abnormalities in patients with a malignant disease has led to a number of studies on their potential role in cancer development. Investigations of families with hereditary cancers and constitutional chromosomal abnormalities have been key observations leading to the molecular identification of specific genes implicated in tumorigenesis. Large studies have been reported on the incidence of constitutional chromosomal aberrations in patients with hematologic malignancies, but they could not confirm an increased risk for hematologic malignancy among carriers of structural chromosomal changes. However, it is of particular interest that constitutional structural aberrations with breakpoints similar to leukemia-associated specific breakpoints have been reported in patients with hematologic malignancies. Because of insufficient data, it remains still unclear if these aberrations represent random events or are associated with malignancy. There has been a substantial discussion about mechanisms involved in constitutional structural chromosomal changes in the literature. The documentation of more patients with constitutional structural chromosomal changes could be of major importance. Most importantly, the molecular investigation of chromosomal regions involved in rearrangements could give useful information on the genetic events underlying constitutional anomalies, contributing to isolation of genes important in the development of the neoplastic process. Regarding constitutional anomalies in patients with hematologic disorders, a survey of the cytogenetic data of our cytogenetics unit is herein also presented.

Cancer risk in patients with constitutional chromosome deletions: a nationwide British cohort study

The finding of increased risks of specific cancers in individuals with constitutional deletions of chromosomes 11p and 13q led to the discovery of cancer predisposition genes at these locations, but there have been no systematic studies of cancer risks in patients with constitutional deletions, across the chromosome complement. Therefore, we assessed cancer incidence in comparison with national cancer incidence rates in a follow-up of 2561 patients with constitutional autosomal chromosome deletions diagnosed by microscopy or fluorescence in situ hybridisation in Britain during the period 1965-2002. Thirty cancers other than non-melanoma skin cancer occurred in the cohort (standardised incidence ratio (SIR)=2.4, 95% confidence interval (CI) 1.6-3.5). There were significantly increased risks of renal cancer in persons with 11p deletions (SIR=1869, 95% CI 751-3850; P=4 x 10(-21)), eye cancer with 13q deletions (SIR=1084, 95% CI 295-2775; P=2 x 10(-11)), and anogenital cancer with 11q deletions (SIR=305, 95% CI 63-890; P=3 x 10(-7)); all the three latter cancers were in the 11 subjects with 11q24 deletions. The results strongly suggest that in addition to suppressor genes relating to Wilms' tumour risk on 11p and retinoblastoma on 13q, there are suppressor genes around 11q24 that greatly affect anogenital cancer risk.

The prognosis for patients with chronic myeloid leukemia who have clonal cytogenetic abnormalities in philadelphia chromosome-negative cells

BACKGROUND

Clonal cytogenetic abnormalities (CCA) were detected in Philadelphia chromosome (Ph)-negative cells in some patients with chronic myeloid leukemia (CML) who attained a cytogenetic response to imatinib mesylate. In some patients, CCA/Ph-negative status was associated with myelodysplasia or acute myeloid leukemia. The objective of the current study was to determine the prognostic impact of CCA/Ph-negative cells.

METHODS

The authors compared the pretherapeutic risk factors (Kruskall-Wallis test), exposure to cytotoxic drugs (chi-square test), and overall and progression-free survival (Kaplan-Meyer and logistic regression analysis, respectively) of 515 patients with mostly chronic-phase CML who were treated with imatinib mesylate after failure of interferon-alpha according to whether they attained a major cytogenetic response (MCR) (n = 324 patients), an MCR with CCA/Ph-negative status (n = 30 patients), or no MCR (n = 161 patients).

RESULTS

CCA/Ph-negative status most frequently involved chromosomes Y, 8, and 7. No significant differences in pretherapeutic risk factors were detected between patients who attained an MCR with and without CCA/Ph-negative cells, except that exposure to alkylating agents was more frequent in patients with CCA/Ph-negative cells, and overall and progression-free survival were identical. With a median follow-up of 51 months, only 2 patients developed myelodysplastic syndromes (MDS).

CONCLUSIONS

The overall prognosis for patients who had CML with CCA/Ph-negative status was good and was driven by the CML response to imatinib mesylate. Isolated CCA/Ph-negative cells in the absence of morphologic evidence of MDS do not justify a change in therapy.

Syndromes and constitutional chromosomal abnormalities associated with Wilms tumour

Wilms tumour has been reported in association with over 50 different clinical conditions and several abnormal constitutional karyotypes. Conclusive evidence of an increased risk of Wilms tumour exists for only a minority of these conditions, including WT1 associated syndromes, familial Wilms tumour, and certain overgrowth conditions such as Beckwith-Wiedemann syndrome. In many reported conditions the rare co-occurrence of Wilms tumour is probably due to chance. However, for several conditions the available evidence cannot either confirm or exclude an increased risk, usually because of the rarity of the syndrome. In addition, emerging evidence suggests that an increased risk of Wilms tumour occurs only in a subset of individuals for some syndromes. The complex clinical and molecular heterogeneity of disorders associated with Wilms tumour, together with the apparent absence of functional links between most of the known predisposition genes, suggests that abrogation of a variety of pathways can promote Wilms tumorigenesis.