Increased Immunoreactivity to SLIT/ROBO1 in Ovarian Endometriomas

Abstract

While surgery is currently the treatment of choice for endometriosis, recurrence remains a serious problem, and its prevention is an unmet clinical need. SLIT, a secreted protein that functions through the Roundabout (ROBO) receptor as a repellent for axon guidance and neuronal migration, has been recently found to induce tumor angiogenesis. We investigated the potential role of SLIT/ROBO1 in ovarian endometriomas and examined their predictive value in recurrence based on tissue samples from 43 patients with recurrence and 45 without recurrence. Microvascular density counts were evaluated by CD34 immunohistochemistry , and statistical analyses were performed to evaluate the effect of SLIT/Robo1 on recurrence risk after adjustment for other risk factors. We found that SLIT expression was positively correlated with microvascular density in ectopic endometrium and that its expression was higher in ectopic endometrium than control endometrium. Both SLIT and Robo1 expression were higher in recurrent cases than in non-recurrent cases. Higher immunoreactivity to SLIT , along with the presence of adhesion , PR-B , and nuclear factor-B , was identified to be a risk factor for recurrence , with a sensitivity of 86% and a specificity of 87%. Therefore , increased SLIT immunoreactivity is likely an important constituent factor for recurrence of ovarian endometriomas, possibly through promoting angiogenesis in ectopic endometrium. Thus, the SLIT/ ROBO1 system may be a potential target for reducing the risk of recurrence. Endometriosis is a common gynecological disorder and a leading cause of disability and loss of productivity in women of reproductive age, and is associated with dysmenorrhea, pelvic pain, and subfertility.1 Due to either poorly documented or limited, short-term, efficacy of medical treatment alone, surgery is currently the treatment of choice for the management of endometriosis. However, recurrence still remains a serious problem: 40% to 45% of patients have a relapse of the disease 5 years after the primary surgery and require further surgeries.2,3 However, repeated surgeries are positively associated with increased morbidity and health care costs and, in endometriosis, with damage to ovarian reserve. 4 -8 Clearly, prevention of recurrence is an unmet clinical need that has not been adequately addressed.The exact causes for recurrence are still poorly understood. Several clinical studies suggest that the recurring endometriotic lesions arise from residual lesions or cells not completely removed during the primary surgery. -11Some other studies suggest, however, that recurrence may originate from de novo lesions derived from endometrium through retrograde menstruation. 12

Increased immunoreactivity to SLIT/ROBO1 and its correlation with severity of dysmenorrhea in adenomyosis

“…Although in endometriosis the involvement of vascular endothelial cell growth factor (VEGF) and other angiogenic mediators has long been recognized (9-12), we have shown recently that SLIT immunoreactivity is increased in endometriosis and its elevation may be a constitutive biomarker for recurrence of endometriosis (13). SLIT is a secretory glycoprotein consisting of three members, SLIT1-3, originally found to be secreted repellents in axon guidance and neuronal migration and shown to be endogenously available inhibitors of leukocyte chemotaxis (14).…”

“…Routine deparaffinization and rehydration procedures were performed, followed by routine immunohistochemical analysis (13). Antibodies to ROBO1, pan-SLIT, and the preimmune IgG were prepared and characterized as reported previously elsewhere (16).…”

Possible Loss of GABAergic Inhibition in Mice With Induced Adenomyosis and Treatment With Epigallocatechin-3-Gallate Attenuates the Loss With Improved Hyperalgesia

“…Immunohistochemical parameters assessed in the area detected included (a) integrated optical density (IOD); (b) total stained area (S); and (c) mean optical density (MOD), which is defined as MOD ¼ IOD/S, equivalent to the mean intensity of stain in all positive cells. Such quantification of immunohistochemistry data has been used satisfactorily as previously reported 27,28 For F4/80, we counted the number of F4/80-positive macrophages from five randomly selected images and calculated their average. The OTR staining scores were calculated by multiplying the percentage of positive OTR cells per section (0-100%) by a semi-quantitative classifier for immunohistochemical staining intensity, which was scored as 0 if there was a complete absence of any staining, 1 for weak staining, 2 for moderate staining, and 3 for strong staining.…”

Aberrant Immunoreactivity of Deoxyribonucleic Acid Methyltransferases in Adenomyosis

“…The positive correlation between SLIT and DNMT1 staining levels in eutopic endometrium was unexpected, but given that SLIT immunoreactivity is found to be correlated with microvascular density in endometriosis [32], endometrial cancer [33] and also in adenomyosis [20], it is possible that increased SLIT staining in eutopic endometrium may increase vascular permeability, resulting in an increased amount of menses. This may explain our finding that higher DNMT1 staining in eutopic endometrium is associated with heavier menses.…”