RESUMEN
BACKGROUND: Borderline ovarian tumors are staged similarly to invasive ovarian tumors. AIMS: We wanted to better understand which tumors were associated with disease recurrence. METHODS: We performed a retrospective cohort analysis at a single institution between 1984 and 2005. Cases were confirmed by pathology report. Multivariate analysis was done to evaluate factors associated with recurrence. RESULTS: 143 cases were identified. Mean follow-up was 73.5 months. The overall risk of recurrence was 12%. The hazard ratio for risk of recurrence was highest among seromucinous tumors at 4.04 and lowest among mucinous tumors at 0.53. Only 4% of mucinous tumors, 15.5% of serous tumors and 28.6% of seromucinous tumors recurred. 2% of mucinous tumors had an appendix positive for metastasis. No mucinous tumor had nodal disease. CONCLUSIONS: Based on our data, a low rate of appendiceal or lymph node involvement was observed in mucinous tumors, as was a low risk of recurrence. Less aggressive staging may be considered if a mucinous tumor is identified on frozen section with a normal-appearing appendix in the absence of pseudomyxoma peritonei. In patients with a serous or a seromucinous tumor, complete surgical staging is recommended. © 2015 S. Karger AG, Basel.
RESUMEN
P-TEFb regulates eukaryotic gene expression at the level of transcription elongation, and is itself controlled by the reversible association of 7SK RNA and an RNA-binding protein HEXIM1 or HEXIM2. In an effort to determine the minimal region of 7SK needed to interact with HEXIM1 in vitro, we found that an oligo comprised of nucleotides 10-48 sufficed. A bid to further narrow down the minimal region of 7SK led to a surprising finding that HEXIM1 binds to double-stranded RNA in a sequence-independent manner. Both dsRNA and 7SK (10-48), but not dsDNA, competed efficiently with full-length 7SK for HEXIM1 binding in vitro. Upon binding dsRNA, a large conformational change was observed in HEXIM1 that allowed the recruitment and inhibition of P-TEFb. Both subcellular fractionation and immunofluorescence demonstrated that, while most HEXIM1 is found in the nucleus, a significant fraction is found in the cytoplasm. Immunoprecipitation experiments demonstrated that both nuclear and cytoplasmic HEXIM1 is associated with RNA. Interestingly, the one microRNA examined (mir-16) was found in HEXIM1 immunoprecipitates, while the small nuclear RNAs, U6 and U2, were not. Our study illuminates novel properties of HEXIM1 both in vitro and in vivo, and suggests that HEXIM1 may be involved in other nuclear and cytoplasmic processes besides controlling P-TEFb.