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The Expression of WT1 in the Differentiation of Rhabdomyosarcoma
from Other Pediatric Small Round Blue Cell Tumors.Mod Pathol
2002;15(10):1080–1086.
The WT1 gene
encodes a transcription factor implicated in normal and neoplastic
development. The purpose of this study was to evaluate the
diagnostic utility of a commercial WT1 antibody on a variety of
pediatric small round blue cell tumors (SRBCT). A mouse monoclonal
antibody (clone: 6F-H2, DAKO) raised against the
N-terminal amino acids 1–181 of the
human WT1 protein was tested. Microscopic sections from 66
specimens were stained using an antigen retrieval protocol with
trypsin. The tumors included peripheral neuroectodermal tumors (PNET/Ewing's),
neuroblastomas, desmoplastic small round cell tumors (DSRCT),
lymphomas, Wilms' tumors, and rhabdomyosarcomas (RMS). One RMS
case was investigated by Western blot analysis and RT-PCR to
confirm the antibody specificity. A strong cytoplasmic staining
was demonstrated in all RMS (11/11). The Western blot analysis
confirmed the WT1 protein in the tissue, and the RT-PCR confirmed
the presence of WT1 mRNA in the peripheral blood and tissue of one
RMS patient. The Wilms' tumors had a variable nuclear and/or
cytoplasmic positivity in most (17/24) cases. All PNET/Ewing's
were negative. The nuclei of two lymphoblastic lymphomas stained
strongly. A weak nuclear or cytoplasmic staining was reported in a
few DSRCT (3/5), lymphomas (2/10), and neuroblastomas (2/8). This
is a useful antibody in the differentiation of RMS from other
SRBCTs. A strong cytoplasmic staining favors an RMS, and a strong
nuclear staining is suggestive of a Wilms' tumor. A role for WT1
in the pathogenesis of rhabdomyosarcomas is raised. The limited
sampling precludes any conclusions regarding the value of tissue
or peripheral blood analysis for WT1 mRNA in patients with
rhabdomyosarcoma.
Frequency of
malignant solid tumors in children.J
Pak Med Assoc. 2000 Mar;50(3):86-8.
OBJECTIVE: To
find out the frequency of malignant solid tumors in children (< 15
years). SETTING: All cases of pediatric malignant solid tumors
which were diagnosed in the section of histopathology at the Aga
Khan University Hospital, Karachi during the period of two years.
METHODS: These tumors were initially evaluated on H&E stained
sections and special stains were also performed whenever
indicated. The undifferentiated tumors were evaluated
immunohistochemically by using a panel of antibodies on sections
from routinely processed, formalin fixed, paraffin embedded tissue
blocks. RESULTS: Of two hundred and fifty three (253) consecutive
cases of paediatric malignant solid tumors, lymphoma (26.1%) was
the most common tumor followed by central nervous system tumors
(16.6%), osteosarcoma (7.5%), rhabdomyosarcoma (6.7%),
neuroblastoma (5.1%), Wilm's tumor (5.1%), Ewing's sarcoma (4.7%),
retinoblastoma (4.7%), germ cell tumor (4.4%) and primitive
neuroectodermal tumor (4%) in order of frequency. In seven cases
(2.8%), the nature of lesion remained undetermined even after
immunohistochemical staining. Rest of malignant tumors (12.3%)
included the rare entities like synovial sarcoma, nasopharyngeal
carcinoma, leiomyosarcoma, malignant schwannoma and thyroid
carcinoma, etc. CONCLUSION: Lymphoma was the most frequent
Paediatric tumor. The frequency of childhood central nervous
system tumors was quite high as compared to the other series from
different regions of Pakistan.
The
pattern of pediatric solid malignant tumors in western Kenya, east
Africa, 1979-1994: an analysis based on histopathologic study.Am
J Trop Med Hyg. 1996 Apr;54(4):343-7.
This
study analyzed histopathologic specimens of 600 pediatric solid
malignant tumors seen during the period 1979-1994 at the
histopathology laboratories of the Rift Valley Provincial General
Hospital in Nakuru, the Nyanza Provincial General Hospital in
Kisumu, and the Uasin Gishu Hospital in Eldoret in western Kenya.
The crude incidence rate of each malignancy per 100,000 children
per year was calculated. The patterns of malignancies were
examined with a focus on tumor incidence, age, sex, geographic,
and ethnic distribution to relate the tumors to putative
environmental and genetic causative factors. The six common tumors
were Burkitt's lymphoma (33.5%), non-Hodgkin's lymphoma (21.8%),
retinoblastoma (11.5%), Kaposi's sarcoma (6.1%), nephroblastoma
(4.5%), and Hodgkin's disease (4.1%). Significantly high crude
incidence rates for lymphomas and Kaposi's sarcoma showed a
characteristic ethnogeographic distribution. The majority of the
tumors were found concentrated around Lake Victoria and showed
decreasing occurrence as one moved towards the semi-arid and
highland areas. We concluded that environmental factors seem to
play a major role in childhood tumors in western Kenya.
Childhood cancer incidence: geographical and temporal variations.
Int J Cancer. 1983 Dec 15;32(6):703-16.
Data from the
first four volumes of Cancer Incidence in Five Continents (CI-5)
and from the first 5 years of the US Surveillance, Epidemiology
and End Results (SEER) program were analyzed for evidence of
geographical and temporal variations in the incidence of selected
childhood tumors. Only lymphoid leukemia and glial neoplasms are
common enough for the observed differences between US registries
to be distinguished from sampling variation. Internationally,
kidney and eye tumors and leukemia show less geographical
variation than do lymphomas and brain tumors, but for none of the
tumors examined is the incidence constant. Wilms' tumor rates
among Japanese, Singapore Chinese and Indians (Bombay) are
approximately 60% of the rates in North America and Britain,
whereas in Scandinavia the rates are up to 30% higher. This
lessens the status of Wilms' tumor as an "index tumor" of
childhood. Areas or countries with especially high or low rates of
other tumors are identified. Rates for glial neoplasms (SEER data)
and Hodgkin's disease (CI-5) are increasing with time in the US,
while brain tumors are being diagnosed more frequently worldwide.
However, the results for brain tumors may largely reflect changes
in pathology diagnosis or reporting practices, and those for
Hodgkin's disease may reflect improvements in case ascertainment.
Otherwise, there is a remarkable stability in the incidence of
selected childhood cancers over time.
Childhood
cancer.Cancer. 1995
Jan 1;75(1 Suppl):395-405.
BACKGROUND. Cancers of individual organs generally are composed of
various histologic types, each with its own frequency and
demographic patterns. For childhood cancers in particular, a
classification of cancers by histologic type is important for
understanding the etiology and progression of the disease.
METHODS. Data from the Surveillance, Epidemiology, and End Results
(SEER) Program on 9308 microscopically confirmed malignant
neoplasms in children younger than age 15, newly diagnosed during
1973-1987, were made available for analysis. Tumors were grouped
histologically according to a classification previously utilized
in an international volume of childhood cancer incidence. RESULTS.
The most frequent histologic types were acute lymphocytic leukemia
(23.6%), astrocytoma (9.6%), neuroblastoma (6.6%), and Wilms'
tumor (6.4%). Acute lymphocytic leukemia accounted for 75% of
childhood leukemia. The most common form of Hodgkin's disease was
the nodular sclerosing subtype, which was diagnosed in 56% of all
cases. Burkitt's and Burkitt-like disease accounted for
approximately one third of non-Hodgkin's lymphoma, the sex ratio
(male to female) being unusually high (5.7). Among the brain
tumors, glioma was of interest because 198 cases (excluded from
this analysis) were diagnosed without histologic
confirmation--due, no doubt, to their inaccessibility for biopsy
because they were located in the brain stem. The most common
histologic type of soft tissue sarcoma was rhabdomyosarcoma, which
accounted for 51% of the total, more than half of which were of
the embryonal type. To the authors' knowledge, this report offers
for the first time the relative frequencies of rare types of
leukemias, such as megakaryoblastic leukemia, in childhood. This
report also includes the frequencies of 21 rarer forms of soft
tissue sarcoma. Five forms of childhood cancer had a 5-year
relative survival rate of 85% or better. Of the cancers with the
poorest outcome, three had relative survival rates of 46.5-49%;
the relative survival rate of acute myelogenous leukemia was only
26.4%. The trends in survival over time for 21 types of childhood
cancer also are included in this report. CONCLUSIONS. Further
refinements in classification now are available through laboratory
techniques utilizing molecular biology, immunology, and
cytogenetics, which are of importance in etiologic studies,
diagnosis, treatment, and prognosis. It would be important in the
future for cancer registries to record the results of relevant
laboratory tests for further analysis by subtype.
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