Journal of Orofacial Sciences

: 2019  |  Volume : 11  |  Issue : 1  |  Page : 55--58

Oral Candidal Carriage Among Patients with Oral Squamous Cell Carcinoma: A Case-Control Study

Sankar Leena Sankari1, Krishnan Mahalakshmi2,  
1 Department of Oral Pathology & Microbiology, Sree Balaji Dental College and Hospital, Bharath Institute of Higher Education and Research (BIHER), Chennai, India
2 Research Lab for Oral Systemic Lab, Sree Balaji Dental College and Hospital, Bharath Institute of Higher Education and Research (BIHER), Chennai, India

Correspondence Address:
Dr. Krishnan Mahalakshmi
Department of Microbiology, Research Lab for Oral Systemic Lab, Sree Balaji Dental College and Hospital, Bharath Institute of Higher Education and Research (BIHER), Chennai


Introduction: Etiology of oral squamous cell carcinoma is multifaceted. The established risk factors include tobacco, alcohol, and immunodeficiency states with infections gaining an importance. Candida species has been implicated in oral squamous cell carcinoma (OSCC). The present study aims at determining the prevalence of Candida species in the saliva of patients with OSCC and healthy cohorts. Materials and Methods: Unstimulated saliva was collected from patients with OSCC (n = 90) and age and sex matched healthy subjects (n = 170). The samples were inoculated onto sabouraud dextrose agar and incubated for a week. The isolates were enumerated using a colony counter. The isolates were identified using standard phenotypic methods. The significance of oral candidal carriage was calculated using chi-square test. Odds and risk ratio was calculated using pearson’s chi-square test. Result: Oral candidal carriage were present in 70% of patients with oscc, while healthy cohorts had a prevalence of 20%. The oral candidal carriage among OSCC patients in comparison to healthy cohorts was highly significant. (p = 0.0001). C. albicans and non-albicans Candida were equally distributed in the OSCC group. Colony-forming units were high among patients with oscc. Significant odds and risk ratio was observed for the prevalence of Candida species among OSCC (p <0.001). Conclusion: The present study shows significant association of oral candidal carriage with OSCC in comparison to healthy cohorts.

How to cite this article:
Sankari SL, Mahalakshmi K. Oral Candidal Carriage Among Patients with Oral Squamous Cell Carcinoma: A Case-Control Study.J Orofac Sci 2019;11:55-58

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Sankari SL, Mahalakshmi K. Oral Candidal Carriage Among Patients with Oral Squamous Cell Carcinoma: A Case-Control Study. J Orofac Sci [serial online] 2019 [cited 2019 Sep 19 ];11:55-58
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Oral squamous cell carcinoma (OSCC) is a major health problem in developing countries and also a leading cause of death. In South-Central Asia, it is the third most common type of cancer.[1] The incidence rates of OSCC are exceptionally high in certain countries such as Papua New Guinea, India, Sri Lanka, Maldives, and Pakistan. [2] Well-established risk factors for OSSC include tobacco usage (smoking/smokeless), areca nut chewing, alcohol consumption, and HPV infections.[3] Several other factors are also recognized to have etiologic roles in OSCC, namely, bacterial and fungal infections, immunosuppression, and malnutrition. There is increasing evidence of the association between Candida infection and OSCC in the recent times. Apart from the ability to produce carcinogens such as nitrosamine, other mechanisms by which Candida spp. may promote the development of cancer have been recently explored, including the metabolism of ethanol to the carcinogenic acetaldehyde and the induction of proinflammatory cytokines.[4]

Candida species have been linked with various precancer and cancer lesions as a causative agent.[5] A considerable proportion of oral squamous cell carcinomas develops from preexisting Candida-associated oral potential malignant disorders. Few studies have also indicated that presence of candidal infection increases the risk of malignant transformation in premalignant lesions.[6] It has been shown that leukoplakia with candidal infection has a higher rate of malignant transformation than uninfected leukoplakia.[7] The virulence mechanism of Candida involved in carcinogenesis is the ability of some species to produce nitrosamines. Highly virulent non-albicans species were able to produce the potent carcinogen N-nitrosobenzylmethylamine.[8] It has also been observed that the level of oral candidal carriage is high in patients presenting with leukoplakia or OSCC than in patients without oral pathology.[9] Hence, the present study was chosen to assess the oral candidal carriage among OSCC patients.

 Materials and Methods

Study population

Ethical approval for this study (Ethical Committee No.: SBDCECM105/13/42) was provided by Ethical Committee of Sree Balaji Dental College and Hospital on November 11, 2013. Informed consent was obtained from all the patients willing to participate in the study. The study population comprised of patients with histopathologically proven oral squamous cell carcinoma (n = 90) and healthy subjects (n = 170). All the patients in this group had habits of smoking and or tobacco chewing along with alcohol consumption. Patients with uncontrolled diabetes and immunocompromised status, denture wearers, and patients receiving steroid therapy and any form of treatment for OSCC were excluded. Subjects with no history of systemic diseases, oral mucosal lesions, and deleterious habits were recruited under healthy controls.


Unstimulated whole saliva was collected by the “draining” method. The subject’s head was tilted forward so that saliva moved toward the anterior region of the mouth and the pooled saliva (2 mL) was collected into a wide-mouthed sterile container.[10] The sample was then immediately transported to the microbiology laboratory for isolation and identification of Candida albicans and non-albicans Candida species. A sample of 10 μL of saliva was inoculated onto Sabouraud dextrose agar plate and incubated at 37°C for 1 week. The purity was checked by Gram staining. Colony count was performed by a digital colony counter and expressed as colony‑forming unit (cfu/mL) of saliva. The identification of Candida species was done by standard phenotypic methods (CHROM agar, germ tube tests, chlamydospore formation on cornmeal agar, sugar assimilation, and fermentation tests). Prevalence, quantification, and identification of the C. albicans and non-albicans Candida isolates were documented.

Data analysis

The significance of oral candidal carriage was calculated using independent T test. Odds and risk ratio with 0.95 confidence interval for prevalence of Candida among OSCC was analyzed using Pearson’s chi-square test. P-value <0.05 was considered significant.


Of the 90 OSCC patients, 72 were males and 18 were females. In the healthy control group, 164 were males and 6 were females. No significant difference was observed between OSCC patients and healthy subjects with respect to age and sex. [Table 1] shows the oral candidal carriage of C. albicans and non-albicans Candida in the study population and control group. In OSCC, the oral candidal carriage was 70%. The percentage of C. albicans and non-albicans Candida was equally distributed. Oral candidal carriage among healthy cohorts was 20%. The prevalence of C. albicans and non-albicans Candida was 55.9 and 44.1%, respectively, in healthy group. A very high statistical significant difference was observed between the study and control groups with respect to oral candidal carriage (p = 0.000). Abundance of Candida colony-forming units (>1000 cfu/mL) was observed in 63.5% among OSCC. Conversely, healthy subjects showed colony-forming units <1000 cfu/mL. In the OSCC group, 11 subjects showed the presence of both C. albicans and non-albicans Candida. Significant odds ratio (9.33) and risk ratio (3.5) were observed for oral candidal carriage in OSCC.{Table 1}


Candida is a normal inhabitant of oral cavity, respiratory tract, digestive system, and genitourinary system.[11] Of the total healthy individuals, 50% carry Candida species as a component of normal oral flora.[12] When ideal conditions supervene, these innocuous commensals increase in their count and cause diseases. [13] Presence of Candida in the mouth together with epithelial changes may predispose to candidal infection. Candidal infection together with other cofactors may also induce epithelial atypia and dysplasia leading to malignant change.[14],[15] The exact role of Candida in inducing dysplasia, atypia, and oncogenesis is not well understood. However, it is recognized that certain C. albicans biotypes are capable of producing carcinogenic nitrosamine N-nitrosobenzylmethylamine.[16] Candida also has the ability to metabolize ethanol into acetaldehyde, a Class I human carcinogen.[17] The possible association between Candida species and oral neoplasia was first reported in the 1960s[18] with later reports suggesting a link between the presence of C. albicans in the oral cavity and the development of OSCC.[19],[20] Nagy et al. found an increase in frequency of C. albicans in biofilms of OSCC tumor sites but never at control sites.[14] McCullough et al. proposed that oral candidal carriage correlated well with both existence and severity of oral epithelial dysplastic and neoplastic development.[9] A case–control study conducted in Italy found association of candidosis with a sixfold increase in oral cancer.[21]

The present study showed a high oral candidal carriage among OSCC patients compared to healthy controls. The oral candidal carriage was observed prior to any form of therapy for OSCC patients. A significant finding in our study was the presence of similar percentage of C. albicans and non-albicans Candida. A vast majority of saliva samples among OSCC population had abundant cfu (63.5%) and nearly 35% of them showed a cfu >1 × 105/mL. The abundant cfu signifies that these Candida species were able to increase in their count in diseases such as OSCC and oral potential malignant disorders conditions. The presence of both C. albicans and non-albicans Candida in 17.5% patients of OSCC was another significant finding in our study.

The oral candidal carriage in OSCC correlated well with studies by Sanjaya (70%)[22] and Saigal et al. (66.6%).[23] The finding of the present study is slightly low compared to Berkovits et al. among OSCC.[24] It is said that anti-inflammatory environment of neoplastic epithelium might support the proliferation of commensal yeasts by suppressing the activity of innate immune cells that are responsible for the limitation of microbial overgrowth.[24] The present study showed a very high presence of oral candidal carriage compared to a study by Galle et al.[25] A meta-analysis reported that Candida infection was 4.92 times more frequent in OSCC patients compared to healthy controls.[26] A significant finding in our study was the presence of similar percentage of C. albicans and non-albicans Candida, which contrasted with other studies where C. albicans was the most frequent species isolated from OSCC patients.[22],[23],[25]

Compared to a few previous studies, the present study reports a higher percentage of oral candidal carriage in healthy subjects.[9],[23],[27],[28] Conversely, we report a low prevalence of Candida in Sri Lankan population compared to Ariyawardana et al. (50%),[13] Zaremba et al. (63.1%),[29] and Mun et al. (48%).[30] The presence of C. albicans isolated in health by Mun et al. (84%) was higher than in the present study. [30]


The present study shows a high incidence of oral candidal carriage in OSCC compared to healthy subjects. This high incidence was observed in OSCC patients before the initiation of therapy for carcinoma. Hence, the oral candidal carriage can be a potential threat to these patients following therapy. Screening of oral candidal carriage and therapeutic planning may decrease the candidal burden in these patients. Further virulence characterization of the Candida species may throw more light on their casual role in OSCC.


The author wishes to acknowledge DST-FIST (Ref. No. SR/FST/College-23, 2017) India for providing research facilities.

Financial support and sponsorship

Bharath Institute of Higher Education and Research.

Conflicts of Interest

There are no conflicts of interest.


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