Detection of Candida albicans in oral squamous cell carcinoma by fluorescence staining technique.

Background: One of the probable etiologic risk factors of oral squamous cell carcinoma (OSCC) is Candidal infection, especially by Candida albicans, whose role has not definitely been confirmed. Some have assigned a primary role to Candida, whereas others consider it as a transient inhabitant. The debate may be due to lack of an accurate and sensitive revealing technique. By identifying the presence of Candida, especially in deeper parts of OSCC, the etiologic role may be verified. The present study was conducted to detect the presence of Candida in OSCC by fluorescence staining technique.

Materials And Methods: This study was descriptive experimental. Calcofluor-white, which is applied in fluorescence staining, is a specific staining substance for Candida and has a higher accuracy compared with other common methods. 100 specimens of well-differentiated OSCC with adequate amount of tissue were retrieved from the archive and two serial sections were obtained from each one. The first section was stained using the popular histochemical (periodic acid-Schiff [PAS]) method and then evaluated under a light microscope to detect the presence of Candida. The second section was stained using fluorescence staining technique. The sum of counted Candida in each technique was fed into SPSS software and analyzed by McNamara test. P < 0.001 was considered as significant.

Results: The amount of Candida present in OSCCs was 74% measured by fluorescence technique. The sensitivity and specificity of the two staining techniques were significantly different. These parameters in the fluorescence technique were higher than those of the histochemical (PAS) method, confirmed by McNamara test showing significantly different results for them (P < 0.001). The results obtained from the fluorescence technique had higher accuracy compared with the histochemical (PAS) method.

Conclusion: Some researchers couldn't find a considerable number of fungi in OSCC, while our results revealed more presence of Candida, especially in deeper parts of tissue samples and probably a more important role for Candida as an etiologic risk factor for OSCC. However, since the fluorescence technique had a higher accuracy in the identification of Candida and it was nearly evident in two-third of the samples, the role of fungi as a primary cause is suggested to be studied in future investigations.