Another important finding of this study is that IMP3 overexpression was frequently expressed (46%) in patients with STIC who had invasive HGSC in the ovary. Although this positive rate is less than the p53 positivity check details (83%) in the same group of cases, the concordant positive staining for both IMP3 and p53 biomarkers was found in 35% of the STIC cases. More interestingly, there were five (10%) STIC cases showing positive IMP3 staining but were negative for
p53 overexpression. These findings suggest that IMP3 staining may aid the diagnosis of STIC, particularly in those cases with negative p53 staining. Although the majority of HGSC in the pelvis is currently classified into tubal primary, particularly when STIC is present [3,7,34], the cancers mainly involving the ovary but without STIC are, by convention, still classified as ovarian primary. Our finding of similar IMP3 expression rate (Table 3) as well as similar clinicopathologic presentations in HGSC with or without STIC supports that HGSC without finding STIC is also likely arising in the fallopian tube [3]. One of the common reasons for not finding STIC in those ovarian HGSCs
is likely due to limited tubal samples examined under microscopy or advanced cancer growth obliterating the tubal fimbria. Based on the findings discussed above, we conclude that IMP3 may involve the initial process of pelvic high-grade serous carcinogenesis and pelvic serous cancer progression. IMP3 may serve as a complimentary biomarker to aid the diagnosis Pifithrin-�� of STIC, particularly when it is negative for p53 immunostaining. However, since this study is mainly on the immunostaining level, detailed molecular mechanism studies are needed to address if tubal epithelia with IMP3 signatures
actually represent a latent precancer and if it has a synergistic role in facilitating cancer development with TP53. Other studies such as the risk of IMP3 signatures in cancer prediction and overexpression of IMP3 in HGSC in relation to patient survival and response to adjuvant therapies are also pertinent in the near future. Acknowledgements Drs. Yiying Wang and Yue Wang were supported by The Health Department of Henan Province, China and Henan Provincial Clomifene People’s Hospital, Zhengzhou, China. The project was supported in part by Better Than Ever Fund, Arizona Cancer Center Supporting Grant, P30 CA23074 from Arizona Cancer Center and Department of Pathology, University of Arizona Startup fund to WXZ. References 1. Cannistra SA: Cancer of the ovary. N Engl J Med 1993, 329:1550–1559.PubMedCrossRef 2. Delair D, Soslow RA: Key features of extrauterine pelvic serous tumours (fallopian tube, ovary, and peritoneum). Histopathology 2012, 61:329–339.PubMedCrossRef 3. Li J, Fadare O, Xiang L, Kong B, Zheng W: Ovarian serous carcinoma: recent concepts on its origin and carcinogenesis. J Hematol Oncol 2012, 5:8.PubMedCentralPubMedCrossRef 4.