Purpose: Interferons are frequently used as an agent in cancer therapy because they possess tumor suppressor activity. The aim of the present work is to investigate the therapeutic role of interferon stimulated gene factor 3 (ISGF3) in different pathological stages of ovarian cancer. Materials and Methods: Sprague Dawley rats were surgically operated along with carcinogen 7,12-Dimethylbenzanthracene (DMBA) to develop ovarian cancer. Histology was used to analyze the grade of ovarian cancer. Immunohistochemistry and Western blotting technique were used to understand the expression of CK7 and ISGF3γ expression. Results: The rat incubated with carcinogen for continuous 18 and 24 weeks were able to develop low and high-grade ovarian cancer respectively. Histologically, low-grade tumor showed more transitional malignant cells while high-grade ovarian cancer showed higher number of proliferative and clumpy cells. The expression of CK7 is constantly overexpressed as tumor pregressed with band intensity of 2.7 and 4.6-fold higher in low and high-grade ovarian cancer. In contrast, interestingly ISGF3γ showed 4.3-fold higher expression in low grade ovarian cancer, but limited with only 1.7-fold higher expression in high grade ovarian cancer. Conclusion: The present results concludes that higher expression of ISGF3γ in low-grade ovarian tumor is due to suppression of tumor development, but in absence of ISGF3γ, expression of tumor development is uncontrolled.