Collagenase digestion of bone marrow trephine biopsy specimens: an important adjunct to haematological diagnosis when marrow aspiration fails.

Failure to obtain sufficient material from marrow aspiration (dry tap) posed a diagnostic problem in two patients with pancytopenia. By using collagenase digestion of the trephine biopsy specimen, a precise diagnosis was reached. This technique is very useful because it permits flow cytometric and immunocytochemical analyses of cell suspensions obtained after collagenase digestion of the trephine biopsy specimen core. Acute leukaemia presenting with a dry tap can therefore be accurately immunophenotyped. The technique is easy to perform and merits wider use.

Granulocytic sarcoma with translocation (9;11)(p22;q23): two cases.

Granulocytic sarcomas are localized deposits of myeloid leukemia cells that may precede or occur concurrently with disseminated disease. In either event, the origins of the cells comprising the malignancy are the same. Published reports of granulocytic sarcomas have described, in the majority of cases, a morphology typical of AML-M2 and the presence of the t(8;21)(q22;q21) typical of that FAB type. In a smaller number of cases, the inv(16)(p13q22) characteristic of AML-M4 has been recorded in cells with a myelomonocytic appearance. We report two patients with granulocytic sarcomas showing monocytic morphology in which the malignant cells showed t(9;11)(p22;q23) typical of AML-M5. This abnormality is seen in up to 7% of childhood AML, but has not previously been reported in granulocytic sarcoma. The detection of this cytogenetic abnormality facilitated the precise characterization of the malignant cells and selection of the most appropriate therapy, emphasizing the value of cytogenetic analysis in cases of granulocytic sarcoma.

Cytogenetic abnormalities in a primitive neuroectodermal tumor.

Two distinct karyotypically abnormal cell lines were observed in cultures of a primitive neuroectodermal tumor. One involved multiple chromosome rearrangements, and the other an inversion of chromosome #7 and a t(3;10) showing an interstitial deletion of 3p; del(3)(p1?4p1?2). None of these rearrangements have been reported in previous descriptions of primitive neuroectodermal tumor karyotypes.

Multiple chromosome rearrangements in a childhood ependymoma.

Multiple karyotypically abnormal cell lines were observed in long-term cultures of an ependymoma of the fourth ventricle of a child. A previous report of a G-banded ependymoma karyotype described monosomy 8, trisomy 9, t(1;7)(p12;p13), and t(X;10)(q22-23;q24). This case also shows involvement of Xq22 and 10q24.

Cytogenetic abnormalities of small round cell tumours.

Between 1987 and 1991, cytogenetic studies were carried out on small round cell tumours of 68 patients from the Northern Health Region of England. Clonal chromosome abnormalities were found in 30, comprising 15 neuroblastomas, 7 Ewing's tumours, 7 rhabdomyosarcomas, and 1 granular cell tumour. Characteristic rearrangements were found in five cases of Ewing's tumour [all with translocation t(11;22) (q24;q12)] and in four cases of rhabdomyosarcoma [all with evidence of translocation t(2;13) (q35-37;q14)]. In one case of Ewing's tumour and three of rhabdomyosarcoma, the cytogenetic findings were important in diagnosis. Within the neuroblastomas, examples were found of hyperdiploidy, 1p rearrangements, double minute chromosomes, and homogeneously staining regions, but too few cases were available for prognostic associations to be assessed. Our findings confirm the diagnostic importance of chromosome abnormalities in small round cell tumours and indicate that cytogenetic analysis should be an intrinsic part of the initial investigations of all patients with such tumours.

Rapid detection of prognostic genetic factors in neuroblastoma using fluorescence in situ hybridisation on tumour imprints and bone marrow smears. United Kingdom Children's Cancer Study Group.

A number of biological factors have been identified which correlate with prognosis in neuroblastoma. Among these are genetic aberrations, including ploidy, deletions of chromosome 1p and N-myc amplification. Conventional methods of detecting these changes, such as tissue culture for karyotyping and Southern blotting, are time-consuming and yield interpretable results in only a small proportion of cases. We have developed interphase fluorescence in situ hybridisation for use on tumour imprints and bone marrow smears, allowing rapid visualisation of the relevant genetic changes. Valuable prognostic information is therefore available in a few days: the results in our cases were later confirmed by conventional methods. In the foreseeable future it will be possible to define distinct prognostic categories on the basis both of this genetic information and other parameters, and separate therapeutic strategies may then be employed for the different patient groups.

Fluorescence in situ hybridization techniques for the rapid detection of genetic prognostic factors in neuroblastoma. United Kingdom Children's Cancer Study Group.

Neuroblastoma is the commonest extracranial solid tumour in children. There are a number of molecular genetic features known which are of prognostic importance and which are used to direct therapy. Identification and targeting of high-risk individuals with intensive therapeutic regimens may allow an improvement in survival rates. The most powerful biological parameters associated with prognosis in this malignancy are chromosomal changes, especially MYCN amplification, deletion of chromosome 1p and aneuploidy. Rapid characterization of these aberrations at the time of diagnosis is paramount if stratification according to risk group is to be achieved. This paper describes the rapid detection of del(1p), MYCN amplification and trisomy using interphase fluorescence in situ hybridization on imprints from fresh tumour biopsies. The results are related to those obtained by standard molecular methods and karyotyping.

Cytogenetically cryptic AML1-ETO and CBF beta-MYH11 gene rearrangements: incidence in 412 cases of acute myeloid leukaemia.

The rearrangements t(8;21)(q22;22) and inv(16)(p13q22) are two of the most frequently seen in acute myeloid leukaemia (AML), accounting for 8% and 4% of cases respectively. Detection of these abnormalities is important for disease management as both are associated with good responses to conventional chemotherapy and prolonged disease-free survival. Recent reports using reverse transcriptase polymerase chain reaction (RT-PCR) suggest that significant proportions of AML cases without a visible t(8;21) or inv(16) show expression of an abnormal fusion gene transcript and, consequently, they could not be detected using conventional cytogenetic analysis alone. We present here a four centre study involving 412 cases of AML screened using both standard cytogenetics and RT-PCR for AML1-ETO and CBF beta-MYH11. We detected a cytogenetic t(8;21) in 31 out of 412 (7.5%) cases and an inv(16) or t(16;16) variant in 27 out of 412 (6.6%) cases. RT-PCR detected only two cases (0.5%) of cryptic t(8;21) and no instances of cryptic inv(16). Both cryptic t(8;21) cases had the classic M2 FAB morphology for this type of disease. Our data concur with the established FAB type distribution of the rearrangements and indicate that cryptic t(8;21) and inv(16) may be much less frequent than reported elsewhere.