CADM1 and TIAM1 Expressions in Mycosis Fungoides: Diagnostic Significance and Association With Histopathological Parameters

BACKGROUND: Mycosis fungoides (MF) is a cutaneous lymphoma that can present various diagnostic challenges. This study aims to evaluate the diagnostic significance of CADM1 and TIAM1 expressions in MF and to assess their association with diagnostic and prognostic histopathological and immunohistochemical parameters. METHODS: In our study, histopathological findings and available CD3, CD4, CD8, CD5, and CD7 immunostaining were evaluated in skin biopsy specimens from 75 MF, 50 inflammatory dermatitis, and 25 control groups. Immunohistochemical CADM1 and TIAM1 staining were applied to all cases. RESULTS: Statistical analyses demonstrated that CADM1 differentiated MF from inflammatory dermatitis and controls with sensitivity of 93.3% and specificity of 88.0%, and early-stage MF from inflammatory dermatitis and controls with sensitivity of 90% and specificity of 88%. CADM1 was found to be significantly elevated in advanced-stage cases and large cell transformation, independent of age and gender. There was a moderate correlation between CADM1 and TIAM1 in the control group, whereas the correlation was weak in the MF group. CONCLUSION: CADM1 is a sensitive and specific diagnostic marker associated with poor prognosis in MF. It is particularly valuable in early-stage cases, where histopathological distinction from inflammatory dermatoses is most challenging. TIAM1 shows no diagnostic or prognostic utility.