Gradual deregulation and loss of PCPH expression in the progression of human laryngeal neoplasia

Abstract

PCPH is a gene involved in the regulation of eukaryotic cell proliferation and stress response. Recently, analyses of human and animal solid tumors and cell lines suggested that PCPH protein deregulation may participate in neoplastic progression. To test this possibility, we first examined PCPH expression in several laryngeal carcinoma cell lines by Western analysis. The results showed the presence of altered PCPH polypeptides in these cells, accompanied by the loss of the PCPH form present in normal laryngeal epithelial cells, a deregulated expression pattern similar to that reported previously. We then analyzed PCPH expression in 59 dysplastic lesions of the human larynx, representative of the mild, moderate, and severe stages of the disease. Immunohistochemical data showed that, compared with normal laryngeal mucosa, PCPH expression in the dysplastic samples was associated with areas of epithelial cell maturation rather than with regions of increased proliferation. Furthermore, PCPH expression decreased parallel to the increase in cellular atypia of the dysplastic samples: PCPH either was expressed at very low levels or not expressed in cases of severe dysplasia/carcinoma in situ. This trend toward loss of PCPH expression along malignant progression of the larynx was confirmed by the low to null expression of PCPH in samples of invasive laryngeal carcinoma and by the complete absence of PCPH immunostaining in a laryngeal carcinoma-derived liver metastasis. These results indicated that PCPH protein analysis might allow for the distinction between grades of laryngeal dysplasia. In addition, detection of altered PCPH polypeptides by Western analysis potentially can be applied to the early identification of laryngeal squamous cell carcinoma.

PCPH expression is an early event in the development of testicular germ cell tumors

“…2-4), a pattern similar to that described previously for PCPH in samples of human laryngeal dysplasia (7), in which PCPH is expressed at lower levels in severe than in mild dysplastic cases and at much lower levels than in the normal laryngeal mucosa (7). The preferential expression of PCPH in well-differentiated slowly proliferating cells rather than in less-differentiated more actively proliferating cells is consistent with the detection in mature teratoma samples of higher levels of PCPH expression in cells of the basal layer than in suprabasal cells (Fig.…”

“…No background staining to PCPH was observed in any of these controls (data not shown). Samples from normal laryngeal mucosa were used as positive controls and yielded results consistent with previously published data (7). Analysis of the seminoma samples showed that PCPH was expressed in all cases.…”

“…Surgical specimens were fixed in a 10% formalin solution at neutral pH for 24-48 h, and embedded in paraffin. Serial sections (6 μM thick) were processed essentially as described (7,8) using an anti-PCPH antiserum (4) at a dilution of 1:4000. In all cases, slides were counterstained with hematoxylin.…”

“…Serial sections of the same samples processed identically but not incubated with the primary antibody were used as negative controls. Positive controls included other human normal and tumor tissues known to express PCPH (5)(6)(7)(8).…”

“…5017, 2004. Because recent analyses of human and animal solid tumors and cell lines indicated that deregulated expression of the PCPH protein is frequently associated with, and thus may participate in, tumor progression (5)(6)(7)(8), it is likely that tumors expressing oncogenic forms of PCPH may be more resistant to radiotherapy and/or chemotherapy.…”