Expression of p63 differs in peritoneal endometriosis, endometriomas, adenomyosis, rectovaginal septum endometriosis, and abdominal wall endometriosis.

ABSTRACT

CONTEXT Although there is evidence that endometriosis results from basal endometrium dislocation, the underlying biology is not fully understood. One protein that plays an important role in regulating epithelial proliferation and differentiation is the 63-kDa membrane protein (p63), which is also a marker of basal and reserve cells in the female genital tract. OBJECTIVE: To determine whether p63 is expressed differently in peritoneal endometriosis, endometriomas, and adenomyosis, as well as in deep endometriotic nodules of the rectovaginal septum and abdominal wall. DESIGN: This study includes a prospective series of consecutive patients (Canadian Task Force classification II-2) from a tertiary care university hospital. Specimens collected from 83 patients (15 peritoneal endometriosis specimens, 22 endometrioma specimens, 36 adenomyosis specimens, and 10 rectovaginal septum/abdominal wall specimens) were evaluated. Diagnostic and operative laparoscopies or laparotomies were performed, and tissue samples were obtained. Immunohistochemistry was used to evaluate p63 expression. RESULTS: Positivity for p63 was detected in 93.3% of the peritoneal endometriosis specimens, 81.8% of the endometrioma specimens, 36.1% of the adenomyosis specimens, and none of the rectovaginal/abdominal wall endometriosis specimens (P < .001). Distribution of p63 immunostaining in the positive specimens was homogeneous. CONCLUSIONS: Endometriotic lesions express p63 differently, and some retain the basal/reserve cell immunophenotype. Nevertheless, it remains unclear whether the lack of p63 expression in some lesions is related to the extent of the disease, to its clinical behavior, or to exacerbation of the accompanying symptoms.