Immunohistochemical detection of p53 in archival formalin-fixed tissues of lip and intraoral squamous cell carcinomas from Norway

• Published in: APMIS : acta pathologica, microbiologica et immunologica Scandinavica microbiologica et immunologica Scandinavica, 1997-10, Vol.105 (7-12), p.757-764
• Main Authors: IBRAHIM, SALAH O., JOHANNESSEN, ANNE C., VASSTRAND, ENDRE N., LILLEHAUG, JOHAN R., NILSEN, RUNE
• Format: Article
• Language: English
• Subjects: Adult; Aged; Antibodies, Monoclonal; Biological and medical sciences; Carcinoma, Squamous Cell - chemistry; Ent. Stomatology; enzyme predigestion; Female; Fixatives; Formaldehyde; Humans; Immunohistochemistry; Investigative techniques, diagnostic techniques (general aspects); Lip Neoplasms - chemistry; Male; Medical sciences; microwave oven heating; Middle Aged; Mouth Neoplasms - chemistry; Norway; oral squamous cell carcinomas; p53 protein; Paraffin; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Time Factors; Tumor Suppressor Protein p53 - analysis
• ISSN: 0903-4641; 1600-0463
• DOI: 10.1111/j.1699-0463.1997.tb05081.x

We investigated the expression of p53 in 82 formalin‐fixed, paraffin‐embedded archival tissue specimens of lip and intraoral squamous cell carcinomas (SCCs) from the period 1930–1995, by immunohistochemistry using three monoclonal antibodies (MAbs DO‐7, DO‐1 and 1801). Before incubation, sections were pretreated with 0.1% Protease® enzyme at 37°C for 10 min followed by 5 + 5 min microwave oven heating at 700 W and 425 W, respectively. Formalin‐fixed tissues of 10 carcinomas of the uterine cervix positive for p53 were used as controls. With one or more of the three MAbs, p53 was expressed in 73% of the 82 SCCs examined. With only protease enzyme pretreatment or microwave oven heating, p53 was expressed in 9/82 and 12/82 of the SCCs, respectively. Of the 82 SCCs, 60%, 45% and 23% expressed p53 with DO‐7, DO‐1 and 1801, respectively. The kappa coefficient indicated poor agreement between these results for the antibodies, and for lip and intraoral SCCs, except for p53 expression in intraoral SCCs demonstrated by DO‐1/1801, which showed fair agreement. The present study suggests that combined protease pretreatment and microwave oven heating of tissue sections improved unmasking of p53 antigenic sites in archival material stored for up to 65 years.