Constitutional balanced translocations in alveolar rhabdomyosarcoma

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.

Cell division cycle control in embryonal and alveolar rhabdomyosarcomas

In this study, we investigated the mRNA level of several genes involved in cell cycle regulation in alveolar (ARMS) and embryonal rhabdomyosarcomas (ERMS). p21(Cip1), Cyclin D1, Cyclin D2, Cyclin D3, CDK2, and CDK4 were evaluated by RT-PCR. All (13 out of 13) ERMS expressed the p21(Cip1) gene compared with only 40% (4 out of 10) of the ARMS. Moreover, the amount of p21(Cip1) mRNA was noticeably higher in the ERMS samples than in the positive ARMS specimens. p27(Kip1) protein were analysed by immunohistochemical and immunoblotting. A noticeable difference was observed, in that ERMS had higher amounts of the cell cycle inhibitor compared with the ARMS. Finally, treatment of two rhabdomyosarcoma cell lines, RH-30 and RD, with butyrate, resulted in complete growth inhibition and in the upregulation of the p21(Cip1) and p27(Kip1) levels. Our results demonstrate that ERMS have a much higher level of p27(Kip1) and p21(Cip1) than the alveolar types, explaining, at least in part, the distinct features and outcomes (i.e. a poor prognosis of the alveolar type) of the two forms of this childhood solid cancer. Moreover, the data on butyrate-treated cell lines suggest that the two genes are potential novel therapeutic targets for the treatment of rhabdomyosarcomas.

Rhabdomyosarcoma: cytogenetics of five cases using fine-needle aspiration samples and review of the literature

Cytogenetic analyses of fine-needle aspiration samples were performed on five cases of which three were alveolar rhabdomyosarcomas (RMS), one was embryonal RMS and one was RMS of mixed alveolar and embryonal histology. Three cases of alveolar RMS and one case of embryonal RMS showed t(2;13). A del(1)(p11) in a mixed alveolar and embryonal RMS was observed without the presence of t(2;13). add(17)(q25) was present in one of the alveolar RMS along with a t(2;13). Modal number of chromosome in the five cases ranged from hyperdiploid to hypertetraploid. Clinical, cytological, histopathological and cytogenetic findings are correlated. The role of additional abnormalities is discussed with a review of appropriate literature.

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.

Cytogenetic abnormalities in 42 rhabdomyosarcoma: a United Kingdom Cancer Cytogenetics Group Study

BACKGROUND

Rhabdomyosarcomas are the most common type of pediatric soft tissue sarcoma. The cytogenetic literature on RMS is biased towards the less common alveolar subtype (ARMS), which is frequently associated with specific translocations and the PAX3/7-FKHR fusion genes. Relatively few karyotypes are reported for the embryonal subtype (ERMS). The aim of this study was to further cytogenetic knowledge of RMS subtypes.

PROCEDURE

Representative examples of all karyotypes from UKCCG; member laboratories were reexamined and their histopathologies reviewed through the United Kingdom Children's Cancer Study (Group) (UKCCSG). Molecular evidence for the PAX3/7-FKHR fusion genes was available for five ERMS and seven ARMS cases and compiled with the karyotypes.

RESULTS

Clonal chro mosome aberrations were characterized for 25 ERMS and 17 ARMS cases. Thirty-six percent of the ERMS cases involved translocation breakpoints in the 1p11-q11 region. Ten of the seventeen cases of ARMS showed cytogenetic evidence for the t(2;13)(q35;q14), consistent with molecular data available from four of these. Two further ARMS cases revealed a PAX3-FKHR and a variant PAX7-FKHR fusion gene product that were not detected cytogenetically.

CONCLUSIONS

Many of the karyotypes from both subtypes were complex. The frequent involvement of the 1p11-1q11 region and gain of chromosomes 2, 8, 12, and 13 in ERMS may be functionally significant. There was no evidence for involvement of the PAX3/7-FKHR genes in ERMS, and cryptic involvement was found in some ARMS. There were no consistent chromosomal rearrangements associated with apparently translocation negative ARMS cases.