Camilla Thellenberg-Karlsson

Estrogen Receptor β Polymorphism Is Associated with Prostate Cancer Risk

Purpose: After cloning of the second estrogen receptor, estrogen receptor β (ERβ) in 1996, increasing evidence of its importance in prostate cancer development has been obtained. ERβ is thought to exert an antiproliferative and proapoptotic effect. We examined whether sequence variants in the ERβ gene are associated with prostate cancer risk. Experimental Design: We conducted a large population-based case-control study (CAncer Prostate in Sweden, CAPS) consisting of 1,415 incident cases of prostate cancer and 801 controls. We evaluated 28 single nucleotide polymorphisms (SNP) spanning the entire ERβ gene from the promoter to the 3′-untranslated region in 94 subjects of the control group. From this, we constructed gene-specific haplotypes and selected four haplotype-tagging SNPs (htSNP: rs2987983, rs1887994, rs1256040, and rs1256062). These four htSNPs were then genotyped in the total study population of 2,216 subjects. Results: There was a statistically significant difference in allele frequency between cases and controls for one of the typed htSNPs (rs2987983), 27% in cases and 24% in controls (P = 0.03). Unconditional logistics regression showed an odds ratio of 1.22 (95% confidence interval, 1.02-1.46) for men carrying the variant allele TC or CC versus the wild-type TT, and an odds ratio of 1.33 (95% confidence interval, 1.08-1.64) for localized cancer. No association of prostate cancer risk with any of the other SNPs or with any haplotypes were seen. Conclusion: We found an association with a SNP located in the promoter region of the ERβ gene and risk of developing prostate cancer. The biological significance of this finding is unclear, but it supports the hypothesis that sequence variation in the promoter region of ERβ is of importance for risk of prostate cancer.

Bone Scan Index as an Imaging Biomarker in Metastatic Castration-resistant Prostate Cancer: A Multicentre Study Based on Patients Treated with Abiraterone Acetate (Zytiga) in Clinical Practice

BACKGROUND Abiraterone acetate (AA) prolongs survival in metastatic castration-resistant prostate cancer (mCRPC) patients. To measure treatment response accurately in bone, quantitative methods are needed. The Bone Scan Index (BSI), a prognostic imaging biomarker, reflects the tumour burden in bone as a percentage of the total skeletal mass calculated from bone scintigraphy. OBJECTIVE To evaluate the value of BSI as a biomarker for outcome evaluation in mCRPC patients on treatment with AA according to clinical routine. DESIGN, SETTING, AND PARTICIPANTS We retrospectively studied 104 mCRPC patients who received AA following disease progression after chemotherapy. All patients underwent whole-body bone scintigraphy before and during AA treatment. Baseline and follow-up BSI data were obtained using EXINI BoneBSI software (EXINI Diagnostics AB, Lund, Sweden). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Associations between change in BSI, clinical parameters at follow-up, and overall survival (OS) were evaluated using the Cox proportional hazards regression models and Kaplan-Meier estimates. Discrimination between variables was assessed using the concordance index (C-index). RESULTS AND LIMITATIONS Patients with an increase in BSI at follow-up of at most 0.30 (n=54) had a significantly longer median survival time than those with an increase of BSI >0.30 (n=50) (median: 16 vs 10 mo; p=0.001). BSI change was also associated with OS in a multivariate Cox analysis including commonly used clinical parameters for prognosis (C-index=0.7; hazard ratio: 1.1; p=0.03). The retrospective design was a limitation. CONCLUSIONS Change in BSI was significantly associated with OS in mCRPC patients undergoing AA treatment following disease progression in a postchemotherapy setting. BSI may be a useful imaging biomarker for outcome evaluation in this group of patients, and it could be a valuable complementary tool in monitoring patients with mCRPC on second-line therapies. PATIENT SUMMARY Bone Scan Index (BSI) change is related to survival time in metastatic castration-resistant prostate cancer (mCRPC) patients on abiraterone acetate. BSI may be a valuable complementary decision-making tool supporting physicians monitoring patients with mCRPC on second-line therapies.

Change in prostate volume during extreme hypo-fractionation analysed with MRI.

BackgroundHypo-fractionated external beam radiotherapy with narrow CTV-PTV margins is increasingly applied for prostate cancer. This demands a precise target definition and knowledge on target location and extension during treatment. It is unclear how increase in fraction size affects changes in prostate volume during treatment. Our aim was to study prostate volume changes during extreme hypo-fractionation (7 × 6.1 Gy) by using sequential MRIs.MethodsTwenty patients treated with extreme hypo-fractionation were recruited from an on-going prospective randomized phase III trial. An MRI scan was done before start of treatment, at mid treatment and at the end of radiotherapy. The prostate was delineated at each MRI and the volume and maximum extension in left-right, anterior-posterior and cranial-caudal directions were measured.ResultsThere was a significant increase in mean prostate volume (14%) at mid treatment as compared to baseline. The prostate volume remained enlarged (9%) at the end of radiotherapy. Prostate swelling was most pronounced in the anterior-posterior and cranial-caudal directions.ConclusionsExtreme hypo-fractionation induced a significant prostate swelling during treatment that was still present at the time of last treatment fraction. Our results indicate that prostate swelling is an important factor to take into account when applying treatment margins during short extreme hypo-fractionation, and that tight margins should be applied with caution.

Platelets harbor prostate cancer biomarkers and the ability to predict therapeutic response to abiraterone in castration resistant patients

Novel therapies for castration resistant prostate cancer (CRPC) have been introduced in the clinic with possibilities for individualized treatment plans. Best practice of those expensive drugs requires predictive biomarker monitoring. This study used circulating biomarker analysis to follow cancer‐derived transcripts implicated in therapy resistance.

Abstract 3158: Prostate cancer derived biomarkers within platelets have the ability to predict therapeutic response in castration resistant patients

Background: Novel therapies for castration resistant prostate cancer (CRPC) have been introduced in the clinic with possibilities for individualized treatment plans. Best practice of those expensive drugs requires predictive biomarker monitoring. In this article a novel platform for circulating biomarker analysis has been used to follow cancer-derived transcripts implicated in therapy resistance. Method: The platelet population of blood samples and QRT-PCR were used to identify selected biomarkers in CRPC patient9s prior chemo- or androgen synthesis (AS)-directed therapies. The association between biomarker statuses (positive vs. negative) and therapy response, progression-free survival (PFS) and overall survival (OS) was examined. Results: 40 patients received either docetaxel (n = 17) or AS-directed (n = 23) therapy, with a therapy response rate of 29% respectively 48%. The cancer-associated biomarkers were present within the platelet fraction. Analyzing these biomarkers in the chemotherapy group were associated with a short OS (p = 0.025). In the AS-directed group, the biomarkers were associated with shorter PFS (p = 0.015), and with an increased risk of therapy failure (HR: 5,5; p = 0,023), as well as short OS (p = 0.012). Conclusions: Analyzing circulating biomarkers in the platelet population enables us to predict who will benefit from AS-directed therapy with high accuracy, and platelet based analysis of cancer derived biomarkers may be used in treatment stratification of patients scheduled for AS-directed therapies. Citation Format: Lee-Ann Tjon-Kon-Fat, Marie Lundholm, Thomas Wurdinger, Camilla Thellenberg-Karlsson, Anders Widmark, Pernilla Wikstrom, Jonas Nilsson. Prostate cancer derived biomarkers within platelets have the ability to predict therapeutic response in castration resistant patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3158.