Figure 2.

A-D. A) The radiogram of blood (=B) and tumour DNA (=T) pairs on TaqI Southern blots probed with the pEP1 probe (encompasses 1000 bp upstream of EGFR exon 1, exon 1 itself and approximately 2000 bp of intron 1). Note the large signal difference between B and T DNA in cases GB23, GB45, GB47, GB242 and GB248 indicating EGFR amplification. Control probing of the same blots with other chromosome 7 and chromosome 2 probes showed loading of DNA to be approximately equal for each of the B and T pairs.

B-C) PCR products using PC66 and PC1403 from some of the AA and GB cases. The case number is given above each lane together with EGFR amplification status (“+” for amplified; “−” for non-amplified). Note that while all tumours show a 923 bp product (indicating presence of the wild-type transcript) some also show a 122 bp product (indicative of the EGFRvIII transcript). A product of the EGFRvIII transcript is shown for GB6 (which had EGFR amplification) as well as in AA94, GB128 and GB13 (which did not fulfil our criteria for EGFR amplification). wt=wild-type; bp=base pair

D) Discriminative RT-PCR using primers PC66 and PC1445. The RNA used was from the same cases shown in Figure 2C and demonstrates the specificity of the reaction with only GB13 showing a positive result (a 125 bp band) from this set of tumours.