Figure 5.

Absence of Fhit protein in H1573 lung cancer cells. The H1573 lung cancer cell line allele a has a translocation between chromosome 3 and 4 (11) at 26.7 kb centromeric to exon 5 so that exons 5–9 are present (with a homozygous deletion within intron 5, ref. 11). Allele b, as shown in Fig. 3, has sustained a deletion within intron 4 (and another in intron 5, ref. 11). Thus, none of the protein-coding exons have been lost through deletion; however, the H1573 cells make very little Fhit protein. (A) Immunostaining with Fhit-specific antiserum of a section of a nude mouse H1573 tumor. (B) Immunostaining (the brown chromagen) of a rare human lung cancer that is positive for Fhit expression.