Immunohistochemical analyses of CD44 variant isoforms in invasive micropapillary carcinoma of the breast: comparison with a concurrent conventional invasive carcinoma of no special type component.
BACKGROUND
Invasive micropapillary carcinoma (IMPC) is a distinct histopathological variant of breast carcinoma and frequently develops lymph node metastases. CD44 is a family of transmembrane glycoprotein receptors with multiple variant isoforms (CD44v), which have tissue-specific expression. Previous studies have demonstrated a loss or gain of CD44v and CD44 standard form (CD44s) expression in breast carcinomas. In this study, we analyzed the immunoprofiles of CD44s, CD44v6, and CD44v9 in IMPC and compared them with those in a concurrent invasive carcinoma of no special type (ICNST) component, thus clarifying the significance of CD44 expression in IMPC.


METHODS
Twenty-one consecutive cases of mixed IMPC were included in this study. The expression statuses of CD44s, CD44v6, and CD44v9 in both the IMPC and ICNST components were analyzed semiquantitatively by immunohistochemistry.


RESULTS
The immunohistochemical scores of CD44s, CD44v6, and CD44v9 were significantly decreased in the IMPC component compared to the ICNST component (p = 0.00335 for CD44s, p = 0.000982 for CD44v6, and p = 0.00271 for CD44v9). Moreover, the immunohistochemical scores of CD44v6 in the IMPC component and CD44v9 in the ICNST component of lymph node metastasis cases were significantly lower compared to cases without lymph node metastasis (p < 0.01).


CONCLUSIONS
Decreased CD44 expression may play an important role in promoting lymph node metastasis in IMPC through an inability or decreased capacity to bind with the surrounding stroma. Moreover, high CD44s+expression levels in the concurrent ICNST component may be related to the development of IMPC.
Department of Surgery, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan.
Tomoko
T
Umeda
Department of Clinical Laboratory Medicine and Division of Diagnostic Pathology, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan. mitsuaki@belle.shiga-med.ac.jp.
Mitsuaki
M
Ishida
Department of Surgery, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan.
Satoshi
S
Murata
Department of Surgery, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan.
Tsuyoshi
T
Mori
Department of Surgery, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan.
Yuki
Y
Kawai
Department of Surgery, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan.
Naoko
N
Itoi
Department of Surgery, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan.
Kaori
K
Tomida
Department of Surgery, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan.
Akie
A
Tanaka
Department of Surgery, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan.
Sachiko
S
Sakai
Department of Surgery, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan.
Mina
M
Kitamura
Department of Surgery, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan.
Yoshihiro
Y
Kubota
Department of Clinical Laboratory Medicine and Division of Diagnostic Pathology, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan.
Ryoji
R
Kushima
Department of Surgery, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan.
Masaji
M
Tani
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D002291:Carcinoma, Papillary / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D018960:Hyaluronan Receptors / Q000032:analysis* / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods*; D008207:Lymphatic Metastasis / Q000473:pathology; D008875:Middle Aged; D020033:Protein Isoforms / Q000032:analysis / Q000378:metabolism
C497483:CD44 protein, human; D018960:Hyaluronan Receptors; D020033:Protein Isoforms
CD44; CD44 variant isoforms; Invasive micropapillary carcinoma; Lymph node metastasis