Several reports have shown that a long delay between cutting sections and immunohistochemical (IHC) staining can decrease the IHC reaction intensity. However, systematic large-scale studies to investigate to what extent this problem may influence the outcome of translational research studies are lacking. In this study, we used a tissue microarray (TMA) approach to investigate the influence of slide age on comparisons between the results of IHC analyses for estrogen receptor (ER), progesterone receptor (PR), cyclin D1, HER2 (HercepTest), and E-cadherin and clinical outcome in a series of 522 breast cancer patients. Old TMA sections stored for 6 months at 41C and freshly cut sections were analyzed under exactly identical experimental conditions. As compared to results obtained on freshly cut sections, the frequency of positivity on old sections decreased from 65 to 46% for ER (Po0.0001), from 33 to 18.5% for PR (Po0.0001), from 16.3 to 9.6% for HER2 (P ¼ 0.0047), from 45.1 to 37.7% for cyclin D1 (P ¼ 0.10), and from 58.9 to 32.9% for E-cadherin (Po0.0001). Despite the lower fraction of positive cases, most associations between IHC data and tumor phenotype that were observed in fresh section analysis were also found when old section data were analyzed. The results confirm that slide aging has a great influence on the intensity of IHC staining in individual cases, but they also suggest that many clinicopathological associations can be detected if suboptimally processed sections are used for IHC.

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Epidermal Growth Factor (EGF) has been localised by immuno-staining to granules of the convoluted duct cells of the submaxillary glands of mice. Improved techniques of freeze drying and formaldehyde vapour fixation have resulted in a light microscopical localisation sharper than was achieved by previous methods. EGF has also been identified by electron immunocytochemistry using the unlabelled antibody enzyme method. EGF is present in greater quantities in male mice than in female mice but in pregnant females the level of EGF in the submaxillary gland is equal to that of the male. It declines gradually during the three weeks of lactation. In view of the chemical similarity between mouse EGF and human Urogastrone these improved methods of identification may be useful in the localisation of the human substance.

Epithelial endocrine cells containing 5-hydroxytryptamine, substance P, somatostatin, enteroglucagon and vasoactive intestinal polypeptide-immunoreactivity were localized by immunocytochemistry in the mucosa of normal appendices, ileum and proximal colon, and in neurogenic appendicopathy. In neurogenic appendicopathy a large number of proliferating nerves were visualized independently of neurotransmitters by immunostaining for neuron-specific enolase. A large number of nerve fibers were shown to contain substance P-immunoreactivity and to be of intrinsic origin. Stromal endocrine cells containing 5-hydroxytryptamine, somatostatin- and possibly substance P-immunoreactivity, were observed in substantial numbers in neurogenic appendicopathy. Substance P may be involved as a neurotransmitter and/or as a paracrine/endocrine peptide in the pathogenesis of spastic contractions and abnormal peristalsis of the appendix, which are characteristic of neurogenic appendicopathy. Stromal endocrine cells may be considered to be the origin of certain carcinoids in the appendix.