COMPARISON OF LABELING BY BROMODEOXYURIDINE, MIB-1, AND PROLIFERATINGCELL NUCLEAR ANTIGEN IN GASTRIC-MUCOSAL BIOPSY SPECIMENS

Aims-To compare proliferating cell nuclear antigen (PCNA) and MIB-1 wi th bromodeoxyuridine (BrdU) pulse labelling, a specific marker of cell proliferation, in endoscopic gastric biopsy specimens. Methods-Twenty four biopsy specimens were obtained from 12 patients: 10 antral and e ight body specimens were suitable. Each specimen was routinely process ed and stained with haematoxylin and eosin. A modified Giemsa stain wa s used to detect the presence of Helicobacter pylori. Sections of the specimens were labelled with BrdU, MIB-1, and PC10. Gastric mucosa spe cimens were divided into three zones. The numbers of positively staini ng nuclei for 500 epithelial cell nuclei were counted in each zone and expressed as a percentage. Results-The proportion of PCNA positive ce lls (range 0-90%) was much greater in all specimens (10 antrum, eight body). BrdU positive cells were virtually all confined to zone 2 (0-17 % cells in this zone were positive) (zone 1 = surface and gastric pit, zone 2 = isthmus, zone 3 = gland base), while PCNA positive cells wer e present in all three zones (1 = 23-90%, 2 = 43-90%, 3 = 0-74%). Spea rman's rank coefficient correlation of 0 57 confirmed that the percent age of positively staining cells varied in the same direction for both PCNA and BrdU (p < 0.001). PCNA, however, was overexpressed in all zo nes of the gastric epithelium compared with BrdU. In 38 biopsy specime ns from 19 patients, of which 14 antrum and 11 body were suitable, the proportion of MIB-1 positive cells (0-59%) was greater than BrdU in m ost. As with BrdU labelling, the MIB-1 positive cells were confined to zone 2 (zone 1 = 1-11%); zone 2 = 21-59%; zone 3 = 0-13%) and the coe fficient correlation for MIB-1 and BrdU was 0.63 (p < 0.001). Conclusi ons-MIB-1 accurately reflects the S-phase fraction in gastric mucosa, determined by BrdU labelling in conventionally processed gastric biops y material. Caution is needed in the interpretation of PCNA labelling detected by PC10, which should not be accepted uncritically as a marke r of cell proliferation in paraffin wax embedded material.