Constitutional balanced translocations in patients with solid tumors

Renal cell carcinoma and a constitutional t(11;22)(q23;q11.2): case report and review of the potential link between the constitutional t(11;22) and cancer

We observed a t(11;22)(q23-24;q11.2-12) and monosomy 3 in renal tumor cells from a 72-year-old man. The hypothesis of a primitive peripheral neuroectodermal tumor (PPNET) located in the kidney was promptly excluded: Histologically, the tumor was a clear cell renal cell carcinoma (RCC) and we did not observe an EWSR1 gene rearrangement. The constitutional origin of this alteration was established. We report on the second case of RCC in a patient with a constitutional t(11;22). The t(11;22)(q23;q11.2) is the main recurrent germline translocation in humans. Unbalanced translocation can be transmitted to the progeny and can cause Emanuel syndrome. Our observation alerts cancer cytogeneticists to the fortuitous discovery of the constitutional t(11;22) in tumor cells. This translocation appears grossly similar to the t(11;22)(q24;q12) of PPNET and should be evoked if present in all cells of a tumor other than PPNET. This is important when providing appropriate genetic counseling. Moreover, the potential oncogenic role of the t(11;22) and its predisposing risk of cancer are under debate. The family history of the patient revealed a disabled brother who died at an early age from colon cancer and a sister with breast cancer. This observation reopens the issue of a link between the constitutional t(11;22) and cancer, and the utility of cancer prevention workups for t(11;22) carriers.

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

We measured the occurrence of cancer in an unselected cohort of carriers of constitutional structural rearrangements in virtually complete nationwide registries for cancer and constitutional cytogenetic abnormalities. We identified 4,816 carriers of a constitutional structural rearrangement in the Danish Cytogenetic Registry and searched for cancer diagnoses by linkage to the Danish Cancer Registry. There was no overall increased risk for cancer among carriers (standardized incidence ratio [SIR], 0.96; 95% confidence interval [CI], 0.84-1.10), and no significant difference from that expected was found in balanced and unbalanced rearrangements or in any subtypes of rearrangements. We found significantly lower risks for carriers with rearrangements involving chromosome 21 (SIR, 0.50; 95% CI, 0.22-0.99) and for paternally inherited rearrangements (SIR, 0.30; 95% CI, 0.06-0.88). Risk estimates for the observed type-specific cancers showed an increased risk for non-Hodgkin lymphoma (SIR, 2.11; 95% CI, 1.09-3.69). However, subgroup analyses were not guided by study hypotheses, and our statistical evaluation of the data should be looked upon as exploratory. In addition, we found 12 constitutional structural rearrangements with a breakpoint potentially associated with a cancer-related gene. Potential new loci associated with type-specific cancers were suggested by the findings of families with more than one affected carrier and by the involvement of the same cytogenetic bands in unrelated carriers. Molecular mapping of these breakpoints might provide new insight into cancer predisposition.

Constitutional t(5;7)(q11;p15) rearranged to acquire monosomy7q and trisomy 1q in a patient with myelodysplastic syndrome transforming to acute myelocytic leukemia

We report the case of a 61-year-old woman who presented with a myelodysplastic syndrome (MDS) and a t(5;7)(q11.2;p15) in her bone marrow cells. Subsequent analysis of phytohemagglutinin-stimulated peripheral blood lymphocytes and cultured skin fibroblasts showed that the translocation was constitutional. Disruption of chromosome bands 5q11.2 and 7p15 has been described recurrently in MDS and acute myelocytic leukemia (AML) and, although the age of onset was not earlier than usual, it is nonetheless possible that genes interrupted by this translocation may been a predisposing factor for her condition. With progression to AML, a further rearrangement of the constitutional der(7)t(5;7) occurred, involving chromosome arm 1q. Fluorescence in situ hybridization (FISH) with whole-chromosome paints showed that the result of the second rearrangement, a t(1;7)(q32.1;q32), was observed, leading to trisomy of the segment 1q32.1 approximately qter and monosomy of the segment 7q32.1 approximately qter. The acquired imbalances, particularly loss of 7q, are commonly associated with MDS/AML and a poor prognosis; however, this patient remained in remission after treatment for more than two years before AML relapse, perhaps because the affected regions fall outside of the critical regions of imbalance.

Constitutional chromosome aberrations as pathogenetic events in hematologic malignancies

A predisposition to tumor development is associated with some constitutional chromosomal abnormalities. Investigations of families with an apparent hereditary cancer and constitutional chromosome rearrangements have led to the molecular identification of tumor suppressor genes. Under the somatic mutation theory for the development of cancer, two mutational events are required. The first step may be a constitutional event and the second an acquired genetic mutation. Cytogenetic studies were performed on 5633 bone marrow specimens from patients with hematologic malignancies from a single institution. Fifty cases of constitutional chromosome aberrations were detected. Data collected from the literature and from our series are reviewed and compared with the incidence of specific constitutional chromosome aberrations in the newborn population. Possible mechanisms that may predispose individuals with constitutional chromosome aberrations to the development of a hematologic malignancy are reviewed.

Constitutional t(16;22)(p13.3;q11.2 approximately 12) in a primitive neuroectodermal tumor of the pineal region

Constitutional chromosome anomalies are known to determine an increased risk of malignancy in certain disorders. We report the case of a 6-month-old female with a primitive neuroectodermal tumor (PNET) of the pineal region and a constitutional reciprocal translocation t(16;22)(p13.3;q11.2 approximately 12). The clustering of cancer chromosome breakpoints to specific chromosome regions is a well-documented phenomenon, with breakpoints on chromosome 22q11.2 approximately 12 having been identified in several subtypes of small round cell tumors. The finding of a 22q11.2 approximately 12 breakpoint in this patient suggests this constitutional translocation may somehow have predisposed the patient to the development of the tumor.

Recurring breakpoints of 1p13 approximately p22 in osteochondroma

Cytogenetic studies of osteochondromas are scarce but have previously shown recurring clonal aberrations involving chromosome 8. We have studied a series of eight tumors and have found recurring aberrations not only involving chromosome 8, but also chromosome 1 in five of the seven abnormal tumors. Surprisingly, three of the chromosome 1 aberrations involved pericentric inversions. Four tumors showed aberrations involving the region 1p13 approximately p22 by mechanisms including inversion, insertion, and translocation. These findings indicate that aberrations of chromosome 1p, in a region spanning 1p13 approximately p22, may be nonrandomly involved in the cytogenetic progression of osteochondroma.

Constitutional balanced chromosomal rearrangements and neoplasm in children

A predisposition to tumor development is currently associated with some, but not all, constitutional chromosomal abnormalities. In a series of 578 children, in which conventional cytogenetic investigation was performed on material from various benign and malignant tumors, four boys and one girl were also found to have constitutional balanced chromosomal rearrangements. The figure of 5 in 578 is notable because the reported incidence of balanced rearrangements in newborns is approximately 1 in 450. Thereby suggesting that some, if not all, children with balanced constitutional chromosomal rearrangements have an increased predisposition for neoplasms developing.

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.

Acute megakaryoblastic leukemia in a patient with a familial pericentric inversion of chromosome 8, inv(8)(p23.1q13)

A 7-month-old girl was diagnosed with acute megakaryoblastic leukemia and, at the time of diagnosis, the karyotype was 48-50,XX,+4,+5,del(5)(p13),del(6)(q14), +8,inv(8)(p23.1q13),der(13) t(13;?;?),+19,-20,+21,+22,+mar [cp20]. At relapse, there was clear evidence of her constitutional status as a carrier of the pericentric inversion (8)(p23.1q13). It was a familial inversion affecting the patient's maternal lineage; a history of cancer and bleeding anomalies in carriers of the inversion led us to consider their nonrandom association with these pathologies.

A case report of Down syndrome and centroblastic lymphoma

We describe a case of left cervical stage I centroblastic lymphoma in a 29-year old male patient with Down's syndrome due to a (14; 21) Robertsonian translocation. The disease presented as extensive lymph node necrosis leaving rare areas of tumor cells, accounting for the diagnostic difficulties. According to our review of the literature, lymphoma is one of the most common neoplasms in DS patients and may represent the second most common malignancy in this condition, far behind leukemia.

Impact of rearrangements on function and position of chromosomes in the interphase nucleus and on human genetic disorders

A synthesis of numerous published data and my own observations reveal that chromatin structure in interphase is functional, dynamic and complex. I hypothesize that: (1) chromosome regions organize nuclear structures and thus their own environment (address themselves in sites and condensation patterns most appropriate for their functional state in the particular cell); (2) chromosome rearrangement could alter nuclear architecture and thus function; and (3) these ideas can explain the contribution of chromosome rearrangements, even in a balanced form, to human pathologic conditions.