CD44 Standard and Variants Expression in Cutaneous T Cell Lymphoma

Hur, Jun; Suh, Kee Suck; Kim, Sang Tae

Abstract

BACKGROUND: CD44 is a family of glycoproteins involved in cell to cell and cell to matrix interactions. Overexpression of CD44v6(variant exon 6) form has been reported in several malignant tumors such as stomach cancer, uterine cervical cancer, colorectal cancer, breast cancer and keratinocytic skin tumors, such as, basal cell carcinoma and squamous cell carcinoma. However, CD44 expression in cutaneous T cell lymphoma has not been investigated thoroughly.
OBJECTIVE
The purpose of this study is to examine whether there is any difference in the expression of CD44s & CD44v6 between mycosis fungoides(MF), angiocentric T cell lymphoma, subcutaneous panniculitic T cell lymphoma, Ki lymphoma and unspecified peripheral T cell lymphoma. We also evaluated the statistical significance between the expression of CD44v6 and systemic involvement of the diseases.
METHODS
Routine paraffin sections of formalin-fixed 33 tissues (11 MF, 8 angiocentric T cell lymphoma, 5 subcutaneous panniculitic T cell lymphoma, 2 Ki lymphoma, 1 unspecified peripheral T cell lymphoma, 2 psoriasis, 2 lichen planus, 2 erythema nodosum) were labeled with anti-CD44 monoclonal antibody using a avidin-biotin-peroxidase complex. Normal skin served as the negative control.
RESULTS
1. Eccrine glands, hair follicles and the epidermis, except the cornified layer, showed positive staining for CD44s. In inflammatory skin diseases, it showed positive staining for CD44s, however CD44v4/5 and CD44v6 stainings were negative. 2. All(4 out of 4) of the tumor stages of MF showed positive CD44s staining, and 3 out of 4 showed positive CD44v6 staining(p=0.024). However, none of them expressed CD44v4/5. 3. All 8 cases of angiocentric T cell lymphoma were positively stained for CD44s, but not for CD44v4/5. In contrast to other peripheral T cell lymphoma, CD44v6 was expressed in 3 out of 8 cases of angiocentric T cell lymphoma. In subcutaneous T cell lymphoma, only the CD44s was expressed, and Ki lymphoma was positively stained for CD44s and negatively stained for CD44v4/5 and CD44v6. 4. In CD44v6 positive angiocentric T cell lymphoma (3 out of 8) and CD44v6 positive tumor stages of MF (3 out of 4), 5 out of 6 patients had systemic involvement suggesting a statistical significance between CD44v6 expression and patient's systemic involvement(p=0.015).
CONCLUSION
These results suggest that CD44v6 may serve as a useful prognostic marker in the tumor stage of mycosis fungoides and angiocentric T cell lymphomas.