Proliferating cell nuclear antigen/cyclin in cultured human keratinocytes

Multiple verrucous carcinomas treated with acitretin

Cutaneous verrucous carcinoma is a rare variant of low-grade squamous cell carcinoma. It usually involves distal extremities and is often misdiagnosed as giant warts. Multiple cutaneous verrucous carcinomas are rare in the English-language literature. We describe a 41-year-old man with multiple verrucous plaques on both feet and ankles, as well as the left thigh. Immunohistochemical study with proliferating cell nuclear antigen revealed positive staining of the basal and suprabasal layers. The patient's condition was successfully treated with systemic acitretin.

Methodological aspects of the immunostaining of proliferating cell nuclear antigen (PCNA) in cytospin preparations of MCF-7 cell line

Cytospins of a human breast cancer cell line (MCF-7) were studied for the expression of PCNA, a cell cycle-related protein, using a variety of fixation and immunostaining procedures. The best fixative for PCNA was found to be buffered formaldehyde solution at 4 degrees C followed by methanol at 20 degrees C, whereas alcoholic fixatives decreased greatly the PCNA immunoreactivity. Air-drying procedures of cytospins prior to and after fixation greatly undermined the PCNA immunostaining. A modified immunoperoxidase method provided a stronger staining of the PCNA-reactive cells than the alkaline phosphatase anti-alkaline phosphatase (APAAP) technique. PCNA immunoreactivity could be maintained up to 2 mo, putting slides in methanol at -20 degrees C. In conclusion, our report indicates that PCNA is a labile antigen, which may critically be affected by temperature and air-drying procedures.

Proliferating cell nuclear antigen in gallbladder carcinoma

Proliferating cell nuclear antigen (PCNA) expression was studied in 103 gallbladder carcinomas and 23 metastatic lesions as well as in 25 control non-neoplastic gallbladder specimens. Positive nuclear staining was observed in 88% of controls, in 92% of carcinomas and in 70% of metastases. The mean number of positive cells was 21.2% in controls, 44.1% in primary carcinomas and 32% in metastatic cancer cells. Differences which were significant were control v. primary tumour, P < 0.000001; control v. metastasis, P < 0.01 and primary tumour v. metastasis, P < 0.006. In 57 (60%) of the primary tumours there was positive staining in over 40% of tumour cells. We were not able to demonstrate any relationship between macroscopic or microscopic features and PCNA expression. However, tumours confined to the mucosa expressed PCNA more frequently than did more advanced tumours.