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The biological activity of tumor cells seems to be related to some peptides produced in the same neoplastic cytoplasms. Cathepsin D is considered one of these proteins, which is able to promote mitosis and tumor invasion. The effects of cathepsin D have been studied in tumors of the breast, ovary and endometrium, and in few cases of laryngeal cancer. Using an immunohistochemical method, we have attempted to evaluate cathepsin D expression in 17 cases of laryngeal squamous cell carcinoma in comparison with the presence of the same protein in the adjacent normal laryngeal mucosa and in inflammatory cells surrounding the tumor. In 11 cases, cathepsin D was present in more than 50% of neoplastic cells, in 4 cases positive cells were 30-50% of all neoplastic cells, in the last 2 cases less than 30% of neoplastic cells expressed the antigen. In normal respiratory epithelium the expression of cathepsin D was limited to the apex of cells. In flat metaplastic epithelium, we observed a positive reaction of basal and parabasal cells. Such positivity became diffuse to all cellular layers in dysplastic foci. A minimal positivity was also detected in salivary glands and ducts. A strong positivity was present in macrophages around and among tumor cells. Our findings suggest that cathepsin D plays a role in cancerogenesis and growth of laryngeal squamous cell carcinoma. The expression of cathepsin D also in normal and inflammatory cells may influence the quantitation of this antigen in studies in which cytosolic levels of cathepsin D are measured after protein extraction.

An immunohistochemical study was performed on the articular disk and periarticular tissues of the temporo-mandibular joint (TMJ) in order to ascertain the presence of neuroreceptors (NRec) in these sites. The study was carried out with the APAAP technique on tissue samples obtained from 10 subjects without known TMJ disease and from 5 patients with severe TMJ arthritis or arthrosis. The antibodies used were directed against the following antigens: Gliofibrillary Acidic Protein (GFAP), Leu-7, Myelin Basic Protein (MBP), Neurofilaments 68 kD (NF), Neuron Specific Enolase (NSE), S-100 protein (S-100) and Synaptophysin (SYN). This study revealed that Ruffini's-like, Pacini's-like and Golgi's-like receptors can be demonstrated in TMJ periarticular tissues and that free nervous endings are present in the subsynovial but not within the articular disk. In the latter, elongated cytoplasmic processes of chondrocytes demonstrated strong S-100 immunoreactivity but they were unreactive with all other antibodies. These cytoplasmic processes were more abundant and thicker in the samples obtained from patients with diseased TMJ. The results of this study confirm that different NRec are detectable in TMJ periarticular tissues but they are absent within the articular disk. In the latter site, only chondrocytic processes are evident, especially in diseased TMJ, and they might have been confused with nervous endings in previous morphological studies. Nevertheless the absence of immunoreactivity for NF, NSE and SYN proves that they are not of neural origin.

Phosphotyrosine (pTyr) is the product of activation of Epidermal Growth Factor receptor (EGFr) in normal and neoplastic oral keratinocytes. As previous studies revealed that EGFr expression may vary with differentiation in several squamous cell carcinomas (SCC), we investigated the expression of pTyr in 30 cases of oral SCC in which EGFr-immunoreactivity had been previously studied. This study was carried out with monoclonal antibodies using an immunohistochemical APAAP method on formalin-fixed, paraffin-embedded samples. The results of this study show that pTyr is expressed in all cases of oral SCC and that its expression is not correlated with tumor differentiation. The Authors suggest that the mechanism of EGFr-mediated cell differentiation and mitosis might short-circuit EGFr in some instances and lead to the phosphorilation of Tyrosine, probably following the stimulation by other factors. This hypothesis needs to be confirmed by appropriate studies on the dynamic biology of oral squamous cells.

The parotidectomy specimens of 3 HIV-infected patients with lymphoepithelial cysts (CLL) have been used to study, with an immunohistochemical method, the expression of the following antigens in histopathological sections: Cytokeratins, CD3, CD20, CD35, CD68, MAC387, Kappa and Lambda light chains. The purpose of the study was to ascertain if CLL of salivary glands parallel the immunophenotype of extrasalivary systemic lymphadenopathy (LAS). The results of this study show that the epithelial lining of CLL does not derive from preexisting ducts and that the immunophenotype of CLL very closely resembles that of LAS. These features seem to suggest that CLL and LAS are tightly related diseases and that probably surgery is not the elective treatment for this lesion.

The presence and the immunophenotype of Langerhans cells (LC) have been investigated in formalin-fixed, paraffin-embedded biopsies obtained from 14 patients with dental titanium implants in which periimplantar tissues had been removed after different intervals from implant positioning. For the phenotypic characterization of LC and other immunocompetent cells in periimplantar tissues the following antigens have been investigated: CD3, CD20, CD35, CD68, MAC387, S-100 Protein and HLA-DR. The immunohistochemical APAAP method has been employed for antigen detection. The study has revealed that rare LC are detectable in the basal epithelium and in the lamina propria of periimplantar tissues removed after 2 months from implant positioning. In these specimens, LC only showed S-100 Protein reactivity; the mild inflammation which was present in the lamina propria was mainly sustained by B-lymphocytes. In samples from patients with dental implant positioned more than a year before, a higher number of LC was detected; the LC were scattered throughout the epithelium and were also in close contact with abundant T-lymphocytes and macrophages in the lamina propria. In patients with long-standing implants, LC appeared immunoreactive to S-100 Protein and HLA-DR. The results of this study show that LC are present in epithelial and mesenchymal periimplantar soft tissues and that their number seems to increase with the duration of implants. The variation in number and in the phenotype of LC may suggest that LC play a relevant role in the immune interactions between host and dental implants which might be important in the complex mechanisms of integration of implants within bone.

Aim of the present study was to investigate the efficacy of 4 different proteolytic treatments (Ficin, Protease type XIV, Microwave irradiation in Citrate buffer and Microwave irradiation in Lead Tiocyanate), compared to the incubation with buffer only, for the detection of cytokeratins in 10 cases of carcinomas from different organs. The same anti-cytokeratin antibody was applied to two sets of tissue sections, after proteolytic treatment, and the reaction was developed by using a different method (ABC or APAAP) for each set of slides. The semiquantitative evaluation of the specimens demonstrated that the higher number of immunoreactive tumor cells was present after Microwave irradiation in Lead Tiocyanate and, to quite a lesser extent, in Citrate buffer. Ficin and Protease type XIV appeared less effective and in some circumstances, the enzymatic digestion of tumor cells seemed to negatively affect the quality of immunostain. When buffer only was used the percentage of immunoreactive tumor cells was considered to be unreliable for diagnostic purposes. The results of the study seem to suggest that proteolytic pretreatment is essential to avoid false negative results when cytokeratin immunostain is essential in histopathology and that Microwave irradiation in Citrate buffer is eligible as the best procedure.

Aim of the present study was to investigate the immunocytochemical expression of Epidermal Growth Factor receptor (EGFr) in normal oral mucosa and in 12 oral papillomas in which the presence of Human Papilloma Viruses (HPV) had been ascertained through in situ hybridization. The study reveals that in normal oral mucosa EGFr is usually expressed in basal cell layers whereas in oral papillomas EGFr is detectable throughout the whole thickness of the lesions. Furthermore, when HPV type 6 is present (10 cases) in the lesion, the pattern of expression of EGFr is almost exclusively membranous whereas in two HPV type 16-induced papillomas the reaction product with monoclonal anti-EGFr Antibodies appears confined to the intracytoplasmic paranuclear area. The present investigation, therefore, seems to show a peculiar correlation between HPV infection and EGFr immunoreactivity in papillomas of the oral mucosa. The pattern of immunoreactivity appears to be related to the specific type of HPV detectable in the lesion and it may possibly depend on the interactions between host and viral genomes. Those interactions might be different for HPV 6 and HPV 16 and may consequently lead to divergent expression of EGFr.

A silver colloid technique to identify Argyrophilic Organizer Region (AgNOR) was applied to 5 hyperplastic polyps, 5 adenomas with low grade dysplasia, 5 adenomas with high grade dysplasia and 15 adenocarcinomas of the large bowel (5 well differentiated, 5 moderately differentiated and 5 poorly differentiated). The authors suggest the plainness and usefulness of simultaneous application of clumps per cell, AgNORs per clump and total AgNORs counts in the evaluation of neoplastic and preneoplastic lesions of the colon. In fact the results show that the number of clumps per cell is useful to distinguish hyperplastic polyps from adenomas with high grade dysplasia and from all the adenocarcinomas. Using the number of AgNORs per clump there is significant difference between hyperplastic polyps and adenomas with high grade dysplasia and between adenomas with low grade dysplasia and well differentiated adenocarcinomas. Finally the total number of AgNORs can discriminate hyperplastic polyps from adenomas with high grade dysplasia and these from adenomas with low grade dysplasia.

The true nature of Nucleolar Organizer Regions Argyrophilic related proteins (AgNORs) is still unknown, but there is wide agreement that their number expresses the nuclear activity. We undertook an investigation on fifty cases of gastric adenocarcinomas (previously grouped morphologically into well and poorly differentiated) applying together with the AgNOR technique, histochemical (Alcian Blue/PAS, High Iron Diamine) and immunohistochemical methods (alpha-1-antitrypsin, alpha-1-antichymotrypsin and lysozyme). AB/PAS was more frequently positive in well-differentiated adenocarcinomas. On the contrary HID was prevailingly positive in poorly differentiated adenocarcinomas. alpha 1 ACT was expressed in all poorly differentiated adenocarcinomas and in a few well-differentiated adenocarcinomas, whereas lysozyme and alpha 1 AT were never expressed. The AgNORs were more numerous, larger, clumped and irregular in shape in poorly differentiated adenocarcinomas. Considering that alpha 1 ACT reactivity seems to be well correlated with survival and given that there is a good correlation between the aforementioned characteristics of AgNORs and the expression of alpha 1 ACT, our investigation suggests that the four techniques used in this study could be useful to predict the prognosis.