Two members of the cadherin family of intercellular adhesion molecules are found in normal breast tissue: E-(epithelial) cadherin is present in both luminal and myoepithelial cells, whereas P- (placental) cadherin is confined to myoepithelium. There is experimental evidence that loss of E-cadherin is associated with increased invasiveness of malignant cells in vitro, which stimulated us to examine the presence and distribution of E- and P-cadherin in breast carcinomas by means of immunohistochemical staining. E-Cadherin was present in all in situ and invasive ductal carcinomas examined, although it had a patchy distribution and the staining was of variable intensity. However, in 83 per cent of invasive lobular carcinomas and all lobular carcinomas in situ there was complete loss of E-cadherin expression. In the remaining 17 per cent of invasive lobular tumours, E-cadherin appeared to have an abnormal distribution within the cytoplasm with variable expression on the cell membrane. P-Cadherin, by contrast, was absent from all benign breast luminal epithelium and 25 carcinomas of ductal and lobular type. It was found in only one carcinoma of lobular type. We suggest that loss of cell-cell adhesion mediated by E-cadherin plays a part in the characteristic morphology of lobular carcinomas.

S_ary The use of chemotherapy as a form of primary treatment for breast cancer is increasing and, as a result, more resection specimens contain tumours which have been exposed to cytotoxic drugs. We have studied the effects of chemotherapy on the tumour morphology and various biological features of breast carcinoma in a group of 35 patients. These were a group who responded to treatment in a clinical study of the use of primary chemotherapy designed to reduce tumour bulk prior to surgery. Characteristic morphological changes, temporally related to the administration of cytotoxic agents, are seen. The malignant cells become enlarged with vacuolated cytoplasm and vesicular nuclei containing prominent nucleoli; occasionally the nuclei were angular and hyperchromatic. These features are interpreted as degenerative in nature. In 15 cases sufficient material was present in the pretreatment biopsies to compare the grade of the tumours before and after chemotherapy: changes were found in six tumours. Cytotoxic drugs do not induce a consistent pattern of change in the proliferation and apoptotic indices of individual tumours, but there is a tendency to reduce proliferative activity over all the tumours as a group. It was also found that chemotherapy is capable of modifying the expression of the oncoproteins c-erbB-2 and p53 in a minority of cases of breast cancer, usually resulting in an acquisition of immunoreactive oncoprotein. It is important to be aware of these effects when studying breast carcinomas removed after chemotherapy.

The clinico-pathological features of 7 cases of adenomyoepithelioma of the breast with features suggestive of malignancy are presented. There was a high incidence of local tumour recurrence, in 2 cases as high-grade infiltrating carcinoma of the breast of no special type ("ductal", grade III). One patient died as the result of a clinically diagnosed cerebral metastasis. Histological examination of the primary breast tumours reveals two main patterns: (1) tumours consisting in part of typical adenomyoepitheliomas but which merge with areas of obviously invasive malignant cells and (2) neoplasms that have the overall architecture of an adenomyoepithelioma but which, on close examination, are found to contain foci of cellular atypia and increased mitotic activity. The two patterns of tumour exhibit the same clinical behaviour and should be distinguished from adenomyoepitheliomas, which are cytologically bland throughout.

A malignant nerve sheath tumour arising in a longstanding benign schwannoma in a 75-year-old woman is described. Malignant change of this kind is extremely rare; there appear to be only four convincing previously reported cases.

Summary:This study reports six patients with a diagnosis of diverticular disease with associated localized Crohn's colitis who were all treated by segmental resection. Two patients died in the post-operative period from disease unrelated to their colonic pathology. The remaining four patients remain well, show no signs of recurrent disease and have required no further surgery. The behaviour and significance of the two conditions occurring in the same patient is discussed.