Figure 2.

Allelic dosage analysis of p14^ARF and p16^INK4a. Results of differential polymerase chain reaction technique, as described in the text. Negative control: LNZ343 with known deletion of the INK4a-ARF locus. Positive control: HepG2 with an intact INK4-ARF locus. The ratio of DNA fragment intensity in HepG2 between exon 1β or exon 3 and the internal control interferon γ (IFN-γ) was used to normalise the results. In patient Nos 2, 4, 10, and 11, the ratio between exon 1β or exon 3 and IFN-γ was 70–100% of the ratio found in HepG2, suggesting that there was no loss at the INK4a-ARF locus.