Citations

Tumor cell proliferation rate determined by either Ki-67 index or mitotic count (MC) has shown to be a prognostic factor for gastrointestinal neuroendocrine tumors in general, and after its incorporation in the 2010 World Health Organization tumor grading system, it has become essentially mandatory in pathology reports for all gastrointestinal neuroendocrine tumors, regardless of tumor location. Nevertheless, clinical significance for the Ki-67 index or MC has not been well demonstrated in small intestinal neuroendocrine tumor (SINET), especially those without distant metastasis, the majority of which have very low proliferation rates. We assessed the clinical behavior of 130 SINETs in relation to stage, Ki-67 index, MC, and other pathologic features. Most SINETs (86%) were grade 1 and 14% were grade 2. There were no grade 3 tumors or poorly differentiated neuroendocrine carcinomas. On multivariate analysis, age, Ki-67 index >5%, MC >10/50 high-power field, stage IV, and liver metastases were associated with increased risk of death in all patients. When both stage and grade were considered, Ki-67 index >5% was associated with a nearly 4-fold increased risk of death in stage IV cases (n=60). In contrast, Ki-67 index did not show prognostic value for patients with stages I to III disease (n=70), although MC >1/50 high-power field was significantly associated with death on multivariable analysis. Our study confirms that liver metastasis and increased tumor cell proliferation rate are independent prognostic factors for SINETs, but shows that most SINETs have a very low proliferation rate, which limits its value for predicting tumor behavior. By combining staging and grading information, we demonstrate different roles and cutoff values of Ki-67 index and MC in SINET with different stages.

Abstract E26 transformation-specific transcription factor ERG is aberrantly overexpressed in approximately 50% of all human prostate cancer due to TMPRSS2-ERG gene rearrangements. However, mice with prostate-specific transgenic expression of prostate cancer–associated ERG alone fail to develop prostate cancer, highlighting that ERG requires other lesions to drive prostate tumorigenesis. Forkhead box (FOXO) transcription factor FOXO1 is a tumor suppressor that is frequently inactivated in human prostate cancer. Here, we demonstrate that FOXO1, but not other FOXO proteins (FOXO3 and FOXO4), binds and inhibits the transcriptional activity of prostate cancer–associated ERG independently of FOXO1 transcriptional activity. Knockdown of endogenous FOXO1 increased invasion of TMPRSS2–ERG fusion–positive VCaP cells, an effect completely abolished by ERG knockdown. Patient specimen analysis demonstrated that FOXO1 and ERG protein expression inversely correlated in a subset of human prostate cancer. Although human ERG transgene expression or homozygous deletion of Foxo1 alone in the mouse prostate failed to promote tumorigenesis, concomitant ERG transgene expression and Foxo1 deletion resulted in upregulation of ERG target genes, increased cell proliferation, and formation of high-grade prostatic intraepithelial neoplasia. Overall, we provide biochemical and genetic evidence that aberrantly activated ERG cooperates with FOXO1 deficiency to promote prostate tumorigenesis and cell invasion. Our findings enhance understanding of prostate cancer etiology and suggest that the FOXO1–ERG signaling axis can be a potential target for treatment of prostate cancer. Cancer Res; 77(23); 6524–37. ©2017 AACR.

Abstract Purpose: DNA topoisomerase inhibitors are commonly used for treating small-cell lung cancer (SCLC). Tyrosyl-DNA phosphodiesterase (TDP1) repairs DNA damage caused by this class of drugs and may therefore influence treatment outcome. In this study, we investigated whether common TDP1 single-nucleotide polymorphisms (SNP) are associated with overall survival among SCLC patients. Experimental Design: Two TDP1 SNPs (rs942190 and rs2401863) were analyzed in 890 patients from 10 studies in the International Lung Cancer Consortium (ILCCO). The Kaplan–Meier method and Cox regression analyses were used to evaluate genotype associations with overall mortality at 36 months postdiagnosis, adjusting for age, sex, race, and tumor stage. Results: Patients homozygous for the minor allele (GG) of rs942190 had poorer survival compared with those carrying AA alleles, with a HR of 1.36 [95% confidence interval (CI): 1.08–1.72, P = 0.01), but no association with survival was observed for patients carrying the AG genotype (HR = 1.04, 95% CI, 0.84–1.29, P = 0.72). For rs2401863, patients homozygous for the minor allele (CC) tended to have better survival than patients carrying AA alleles (HR = 0.79; 95% CI, 0.61–1.02, P = 0.07). Results from the Genotype Tissue Expression (GTEx) Project, the Encyclopedia of DNA Elements (ENCODE), and the ePOSSUM web application support the potential function of rs942190. Conclusions: We found the rs942190 GG genotype to be associated with relatively poor survival among SCLC patients. Further investigation is needed to confirm the result and to determine whether this genotype may be a predictive marker for treatment efficacy of DNA topoisomerase inhibitors. Clin Cancer Res; 23(24); 7550–7. ©2017 AACR.