Micro-spectroscopic investigation of selenium-bearing minerals from the Western US Phosphate Resource Area

Proliferative activities in 181 primary Borrmann type 4 gastric carcinomas were investigated using percentage labelling of proliferating cell nuclear antigen (PCNA) and an argyrophilic nucleolar organiser region (AgNOR) count. Tumours with a high proliferative activity often metastasised to lymph nodes (P<0.01), and these patients had a lower survival rate (P<0.05). A significant correlation was recognised between the PCNA labelling percentage and AgNOR count (r = 0.452, P< 0.001). Cox's regression analysis showed that PCNA labelling percentage is an independent prognostic factor. These results indicate that estimating proliferative activity may be useful in predicting lymph node metastasis and patients' prognosis in cases of Borrmann type 4 gastric carcinoma. Advanced carcinoma of the stomach can be classified based on Borrmann's criteria into one of four types (1-4) (Borr-mann, 1926). A knowledge of this classification is important for endoscopists, radiologists and surgeons (Borchard, 1990). Of the Borrmann types of carcinomas, type 4 is a diffuse malignant lesion with indistinct borders, and is usually identified only at a very advanced stage (Maehara et al., 1992a). The lack of sharp borders can lead to underestimation of the size. As these cancers grow in the plane of the submucosa beneath an otherwise normal mucosa, establishing the histological diagnosis is difficult (Borchad, 1990). The clinical course is usually unfavourable and the 5 year survival rates are only 0-20% (Furukawa et al., 1988; Maehara et al., 1992a). Though many investigators have studied this entity from various aspects, the biological characteristics of Borrmann type 4 gastric carcinoma remain an open question. As it is now feasible to measure proliferative activities of cells in formalin-fixed paraffin-embedded sections of surgical samples, two parameters of proliferative activity, proliferating cell nuclear antigen (PCNA) and argyrophilic nucleolar organiser regions (AgNOR), were measured. PCNA, a 36 kDa non-histone nuclear polypeptide, is an auxiliary protein of DNA polymerase delta (Bravo et al., 1987), and plays a critical role in the initiation of cell proliferation (Jaskulski et al., 1988). The levels of PCNA increase in the nucleus during the late GI phase immediately prior to the onset of DNA synthesis, become maximal during the S phase, decline again during G2 and are low in M phase and quiescent cells (Kurki et al., 1987). Though PCNA staining has limitations in that the molecule has a long half-life which can also lead to staining of cells which have exited from the cycle (Bravo & Bravo, 1987), it is a …