You are presented with a paragraph from a COVID-19 literature. Classify the topics of this piece of text by choosing from the following categories:

- Epidemic Forecasting: The content relates to predictions about the spread of COVID-19.
- Treatment: The paragraph discusses therapeutic methods or medication for COVID-19.
- Prevention: The content covers measures to prevent the spread of COVID-19.
- Mechanism: The paragraph explains the biological mechanisms of the virus.
- Case Report: The content is a report of a COVID-19 case.
- Transmission: The paragraph discusses how COVID-19 is transmitted.
- Diagnosis: The content is about diagnosing COVID-19 in individuals.

Your classification should be provided as an element within a JSON array. The array should be formatted with topics enclosed in double quotes and separated by commas, following the JSON format, for example: ["Topic1", "Topic2", ...]. Include all applicable topics within the array. Your output should be a valid JSON array, and no additional text should be included in your response.

Article:

OBJECTIVE: The aim of the present case-control study was to evaluate the morphological aspects of the epithelial cells from the dorsum of the tongue and the expression of the SARS-CoV-2 Spike protein in these cells, in patients with and without COVID-19 infection. METHODS: 24 individuals with at least one symptom of COVID-19 were recruited among inpatients from Hospital Universitario Pedro Ernesto (Rio de Janeiro, Brazil). 14 patients who tested positive for COVID-19 by RT-PCR were included in the case group, and 10 patients who tested negative were included in the control group. Cytological smears from the dorsum of the tongue were obtained from all patients and analyzed using immunohistochemistry directed against SARS-CoV-2-Spike protein. Morphological changes in epithelial cells were analyzed using light microscopy. RESULTS: Immunohistochemistry showed that 71% of the COVID-19 patients presented epithelial cells positive for the presence of the SARS-CoV-2 Spike protein, and all cells coming from patients in the control group were negative. Cytological analysis showed significant differences when comparing epithelial cells from COVID-19-positive and COVID-19-negative patients. CONCLUSION: COVID-19 may generate dimensional changes in tongue epithelial cells; however, further studies are necessary to understand how this happens.
["Diagnosis", "Mechanism"]