Immunohistochemical localization of group II phospholipase A2 in the tumours and mucosa of the colon and rectum.

BACKGROUND: Group II phospholipase A(2)(PLA(2)) is an enzyme important in malignant transformation and in the invasion process of malignant cells. The aim of the present study was to investigate the expression of group II PLA(2)in the cancers of the colorectum, peritumoural mucosa and in the mucosa distant from the tumour. METHODS: Resection specimens from 57 patients with colorectal carcinoma (caecum 10, ascending 10, transverse 10, sigmoid colon nine, and rectum 18) were analysed immunohistochemically. Histological slides from paraffin blocks were stained by the human monoclonal group II PLA(2)antibody ('Upstate Biotechnology', Lake Placid, NY 12946, USA. Antibody Class: IgG1k. Immunogen: HPC purifed human sperm phospholipase A(2)- 14 kDa enzyme) using the standard DAKO peroxidase-labelled streptavidin-biotin method by TechMate 500 stainer. Group II PLA(2)expression was evaluated semi-quantitatively according to the extensivity and intensivity of the positive cells. For statistical evaluation the Kruskal-Wallis one way analysis of variance on ranks and the Mann-Whitney rank sum tests were used. RESULTS: The highest expression of group II PLA(2)was found in the peritumoural mucosa (median 4.00), much lower in the mucosa distal from the tumour (median 0.70) and almost no activity in the tumour itself (median 0.00), all differences were statistically significant (all pairwise multiple comparison procedures - Dunn's Method P<0.05). The expression of group II PLA(2)was higher in the left colon and rectum than in the right colon (Mann-Whitney rank sum test P<0.05). CONCLUSIONS: Our results suggest that there is variation of the group II PLA(2)expression throughout the mucosa and tumours of the colorectum, which might reflect the progression of neoplastic process.

Adenoid cystic carcinoma of the breast: a histologic, cytologic, and immunohistochemical study.

Six cases of adenoid cystic carcinoma (ACC) of the breast were reviewed. Immunohistochemical studies were carried out for actin, S-100 protein, EMA, keratin, CEA, vimentin, NSE, alpha-lactalbumin, and lysozyme. Fine needle aspiration biopsy smears of five patients were also reexamined. Patients were treated by tumorectomy, quadrantectomy, or modified radical mastectomy. Axillary dissection was carried out in five cases, with negative lymph nodes in all. Five patients are alive without evidence of disease from 1 year 10 months to 13 years 4 months following surgery. One patient died 7 1/4 years after mastectomy, without evidence of disease. Histologically, a diagnostic biphasic cellular pattern was seen in all cases. In addition, several unusual features were encountered in some cases: squamous metaplasia, stromal myxoid pseudocartilaginous foci, and well-formed neoplastic ducts. Actin and/or S-100 protein were variably positive in all cases. The reaction was usually present in occasional basaloid cells predominantly at the periphery of neoplastic structures. Keratin, EMA, and CEA immunostaining disclosed ductal type cells in all cases. Vimentin was positive in four cases, usually in many basaloid cells. Aspiration cytology was suspicious in two cases and yielded a definitive diagnosis of ACC in three cases. Cytologic diagnosis was based on cellular morphology and on the presence of characteristic globoid structures. Immunohistochemical results show that in ACC dual myoepithelial-ductal differentiation occurs but is relatively limited. Most of the tumor cells are not differentiated ("indifferent" cells) and often express strong vimentin positivity. Such cells are regarded as precursor cells for either differentiated element. Unusual metaplastic changes in breast ACC suggest a possible relation with pleomorphic adenoma-type tumors, and this might be of prognostic significance.