Reverse transcriptase polymerase chain reaction as a reliable method to detect epidermal growth factor receptor exon 2-7 gene deletion in human glioblastomas
K. Worm et al., Reverse transcriptase polymerase chain reaction as a reliable method to detect epidermal growth factor receptor exon 2-7 gene deletion in human glioblastomas, HUMAN PATH, 30(2), 1999, pp. 222-227
Citations number
38
Categorie Soggetti
Research/Laboratory Medicine & Medical Tecnology","Medical Research Diagnosis & Treatment
Epidermal growth factor receptor (EGFR) gene amplification has been reporte
d to occur in diverse carcinoma types such as lung, ovarian, and breast car
cinomas and in glioblastomas. A 801-bp in-frame deletion close to the amino
terminus of the receptor protein has been found to occur more or less frequ
ently within at least three of these tumor entities. We studied EGFR gene a
lterations using the polymerase chain reaction and EGFR gene expression of
65 astrocytic tumors (51 glioblastomas World Health Organization [WHO] IV f
ive anaplastic astrocytomas WHO III, and nine astrocytomas WHO II). EGFR ge
ne amplification, as determined by Southern blotting. using a full-length c
DNA probe, was observed in 22 of 51 glioblastomas (43%) but in none of the
grade II astrocytomas. Two of five anaplastic astrocytomas at WHO In showed
a considerable degree of EGFR amplification but, according to the neurorad
iological data, these two tumors had to be considered as glioblastomas. The
most frequently found genetic alteration was the 801-bp deletion near the
receptor aminoterminus comprising a complete loss of exon 2 to exon 7 (del(
2-7)). We showed that RT-PCR is superior to Southern blot analysis in detec
tion of this type of deletion and can be assigned to 9 of 38 (24%) glioblas
tomas examined. Expression of a EGF receptor protein was enhanced in most o
f the tumors with gene amplification. However, 5 of 18 tumors that express
a receptor protein in the absence of EGFR gene amplification also showed el
evated levels of EGFR gene expression. In addition to the full-length recep
tor protein, a signal in the 140-kDa range was observed in 17 of 35 gliobla
stomas (49%). This fragment may correspond to the truncated del(2-7) recept
or protein or might be due to proteolysis of the full-length receptor prote
in. HUM PATHOL 30:222-227. Copyright (C) 1999 by W.B. Saunders Company.