Nuclear morphometry and glutathione S-transferase pi expression in breast cancer.
Glutathione S-transferase pi (GST-pi) is a phase II detoxification enzyme whose expression is increased in estrogen receptor (ER)-poor breast cancers and in breast cancers resistant to certain chemotherapeutic agents. The aim of this study was to investigate the immunohistochemical expression of GST-pi in invasive breast carcinoma and to correlate the findings with those of nuclear morphometry. Formalin-fixed paraffin-embedded tissue specimens obtained from 21 invasive breast cancers and 16 adjacent (benign) tissues were immunohistochemically stained using polyclonal anti-human GST-pi antibody. There was positive (defined as >10% immunoreactive tumor cells) but variable expression of GST-pi in 10 (48%) cases. Nuclear morphometry in these 10 tumors revealed immunoreactive malignant cells to be larger (mean area 41.7+/-1.0 microm2) and more rounded in form when compared with non-staining cancer cells (mean area 28.7+/-0.7 microm2). It was also observed that GST-pi immunonegative tumor cells in GST-pi expressing tumors had different morphologies from malignant cells in the remaining 11 (52%) cancers that were regarded as GST-pi negative. Increased GST-pi expression determined by the percentage of positively staining tumor cells, was found to be significantly correlated with increased variability in nuclear area and perimeter (Spearman's rho=0.821, p=0.044 for both) in the subset of node-positive tumors. Our findings suggest that there exists two sub-populations of cancer cells with distinct nuclear morphologies in GST-pi positive tumors; factors other than GST-pi expression are likely to have a phenotypic effect on breast cancer cells; and there may be a special significance of this enzyme in axillary node-positive breast tumors.
Huang
J
J
Department of Anatomy, National University of Singapore, Kent Ridge, Singapore S119 260, Republic of Singapore.
Bay
B H
BH
Tan
P H
PH
D001940:Breast / Q000201:enzymology / Q000473:pathology; D001943:Breast Neoplasms / Q000201:enzymology / Q000473:pathology* / Q000601:surgery; D002467:Cell Nucleus / Q000473:pathology*; D005260:Female; D005982:Glutathione Transferase / Q000032:analysis*; D006801:Humans; D007527:Isoenzymes / Q000032:analysis; D008207:Lymphatic Metastasis; D009361:Neoplasm Invasiveness; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis
D007527:Isoenzymes; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D005982:Glutathione Transferase