p53 protein expression in cutaneous squamous cell carcinoma.

BACKGROUND: p53 is a nucleoprotein encoded by a tumor suppressor gene. It's mutations are implicated in the genesis of a wide variety of malignant neoplasia including skin cancers. OBJECTIVE: To study the expression of the p53 protein in cutaneous squamous cell carcinoma (SCCs) and evaluate the relationships between this expression and sites, varying degrees of differentiation and amounts of apoptotic cells. METHOD: Sixty-seven tissue samples of SCCs from Songklanagarind Hospital obtained from January 1991 to December 1996 were examined by immunohistochemistry using polyclonal anti p53-CM1. (Novocastra Laboratories, Newcastle, England, dilution 1:700) RESULT: p53 Immunoreactivity was demonstrated in 26.87 per cent of SCCs. This was observed in 15/51 of sun-exposed cases and 3/16 of sun-protected cases (p = 0.401). The more differentiated the tumor, the less p53 staining was observed (p = 0.043). There was no association between p53 positivity and the amounts of apoptotic cells. CONCLUSION: The p53 expression is not related to the sun exposure. It does not represent a commitment to apoptosis. However, it may indicate the differentiation and/or proliferative status of the tumor cells.

Hematoxylin-lac-curcuma polychrome stain for mucin.

A polychrome method for detection of mucin substance in paraffin section is produced by sequential stepwise staining of hematoxylin, crude lac extract (Laccifer lacca), and crude curcuma extract (khamin shan-Curcuma longa). The name LacCur stain is proposed. After a tissue section is deparaffinized and rehydrated, it is stained with Weigert's hematoxylin for 7 minutes. After a quick wash, it is stained for at least 3 hours with lac dye mordanted with aluminum chloride. Washed again and premordanted with ferric chloride for 1 minute, in the last step, it is counterstained with curcuma dye for 5 minutes. With this staining method, the nuclei are stained black, mucin deep red, and organelles and ground substances brownish yellow. The method and outcome colors are comparable to the widely used Mayer's mucicarmine staining method. It costs less than the Mayer's mucicarmine staining method and the procedure is not complicated.

Precancerous lesion and early carcinoma of the pyriform sinus.

Thirty-five specimens from total laryngopharyngectomy clinically diagnosed as squamous cell carcinoma of the pyriform sinus were studied. Patients receiving chemotherapy or radiotherapy were excluded. Pathological examinations revealed 26 (74.3%) precancerous lesions and early carcinoma of the pyriform sinus. Eight out of 26 cases were detected by gross examination. Most pathological findings were carcinoma in situ (CIS). Epithelial changes of the pyriform sinus were not similar to those of the uterine cervix. They usually showed abrupt change, frequently from normal to CIS, mild dysplasia to invasive carcinoma and these lesions can be detected early by physical examination. Because of multifoci of carcinoma, the concept of "multicentric origin" is proposed.