Stromal reaction of adenomyosis protects from uterine endometrial cancer invasion to myometrium

16064 Background: It is unclear that stromal reaction plays role in endometrial cancer (Em Ca) invasion to uterine muscle with adenomyosis. Methods: One hundred and five patients with Em Ca (stage 0=38, 1a=18, 1b=26, 1c=10, 2b=3, 3a=4, 3c=5, 4a=1) received operative therapy with hysterectomy. Evaluation of stromal reaction using immunohistochemical method with alpha-smooth muscle actin and h-caldesmon antibody. In case of alpha-smooth muscle actin had immunoreactivity and h-caldesmon had not immunoreactivity, there was stromal reaction with myofibroblast. Evaluation of cell proliferation, using immunohistochemical method with epidermal growth factor receptor (EGFR) by global score with six degrees and MIB-1 by labeling Index (LI). Results: All cases had stromal reaction with myofibloblast in myometrial invasion area in forty nine cases with myometrial invasion equal or more than stage 1b. Em Ca invaded near to and in adenomyosis lesion in eleven cases. In stroma of adenomyosis without cancer invasion, EGFR was positive in one case (9%) and global score was two (average 0.18). In contrast, EGFR was positive in eight cases (73%) with Em Ca invasion to adenomyosis stroma and global score was from two to three (average 1.6). LI of MIB-1 was from 0 to 0.2 (average 0.05) in adenomyosis stroma without Em Ca invasion and 0.2 to 0.75 (average 0.41) with Em Ca invasion. Conclusions: When Em Ca invades to adenomyosis, myofibloblast cell proliferation in stromal reaction increases more than in adenomyosis without Em Ca invasion. Stromal reaction of adenomyosis plays role in protecting from Em Ca invasion to uterine muscle and it may contribute to being good prognosis compared with Em Ca without adenomyosis. No significant financial relationships to disclose.