Histone deacetylases (HDACs) 1 and 2 share a high degree of homology and coexist within the same protein complexes. Despite their close association, each possesses unique functions. We show that the upregulation of HDAC2 in colorectal cancer occurred early at the polyp stage, was more robust and occurred more frequently than HDAC1. Similarly, while the expression of HDACs1 and 2 were increased in cervical dysplasia and invasive carcinoma, HDAC2 expression showed a clear demarcation of high-intensity staining at the transition region of dysplasia compared to HDAC1. Upon HDAC2 knockdown, cells displayed an increased number of cellular extensions reminiscent of cell differentiation. There was also an increase in apoptosis, associated with increased p21Cip1/WAF1 expression that was independent of p53. These results suggest that HDACs, especially HDAC2, are important enzymes involved in the early events of carcinogenesis, making them candidate markers for tumor progression and targets for cancer therapy.

Aims-To study the expression and importance (if any) of p53 protein in gall bladder carcinoma and its precursor lesions. Methods-Immunohistochemical staining was performed on formalin fixed, paraffin wax embedded histological sections with an anti-human p53 monoclonal antibody (DO-7; Dako Corporation M7001) (24 carcinomas, one adenocarcinoma in situ, six dysplasias, three adenomas and four cases of chronic cholecystitis). Invasive, in situ, and dysplastic areas as well as normal-looking epithelium were sought. Nuclear Carcinogenesis is a multistep process involving several genetic changes which include activation of cellular proto-oncogenes and inactivation of tumour suppressor genes.7Invasive carcinomas of the gall bladder are often associated with dysplasia and adenocarcinoma in situ changes in the neighbouring epithelium. This association implies a temporal progression or radical change in the process of carcinogenesis and provides a good sequential model for studying the evolution of p53 protein expression in the malignant transformation of gall bladder epithelium. MethodsTwenty four carcinomas of the gall bladder, one adenocarcinoma in situ, six epithelial dysplasias, three adenomas and four cases of chronic cholecystitis were retrieved from the files of the department of pathology, National University Hospital. All the tissue had been fixed in 10% buffered formalin and embedded in paraffin wax. Slides stained with haematoxylin and eosin and periodic acid-Schiff before and after diastase digestion were evaluated. The cases were analysed for invasive, in situ, and dysplastic areas as well as normallooking epithelium.Immunohistochemical staining was performed using a streptavidin-biotin immunoperoxidase method. Waxed sections (4 im) were treated with 3% hydrogen peroxide for 10 minutes to block endogenous peroxidase. The sections were then incubated with 5% bovine serum albumin (BSA) in TRISbuffered saline (TBS) for 30 minutes to eliminate any non-specific staining. Excess BSA was drained from the slides before incubation with an anti-human p53 monoclonal antibody (DO-7; Dako Corporation M7001) at an optimal dilution of 1 in 50 in 0-1% BSA overnight at 4°C. The tissue sections were subsequently washed with TBS and incubated with biotinylated rabbit-anti-mouse immunoglobulin (Dako; E354), 1 in 200 in 0-1% BSA

An experience with six cases of fractured penis is described. A 'rolling sign' accurately identifies clot at the fracture site and facilitates a direct and rapid approach to the torn corpus cavernosum. Early operation hastens recovery and limits deformity.

Squamous metaplasia in the breast is well documented. However, the putative cell of origin for the squamous epithelium is not clear. This paper describes a case of fibroadenoma of the breast with myoepithelial hyperplasia and squamous metaplasia. The histological finding of transition between myoepithelial cells and squamous cells and the immunohistochemical expressions of actin and S-100 in the metaplastic squamous cells support the myoepithelial origin of squamous epithelium in the breast.