In vitro engineering of a bone metastases model allows for study of the effects of antiandrogen therapies in advanced prostate cancer

While androgen-targeted therapies are routinely used in advanced prostate cancer (PCa), their effect is poorly understood in treating bone metastatic lesions and ultimately results in the development of metastatic castrate resistant prostate cancer (mCRPC). Here, we used an all-human microtissue-engineered model of mineralized metastatic tissue combining human osteoprogenitor cells, 3D printing and prostate cancer cells, to assess the effects of the antiandrogens, bicalutamide, and enzalutamide in this microenvironment. We demonstrate that cancer/bone stroma interactions and antiandrogens drive cancer progression in a mineralized microenvironment. Probing the bone microenvironment with enzalutamide led to stronger cancer cell adaptive responses and osteomimicry than bicalutamide. Enzalutamide presented with better treatment response, in line with enzalutamide delaying time to bone-related events and enzalutamide extending survival in mCRPC. The all-human microtissue-engineered model of mineralized metastatic tissue presented here represents a substantial advance to dissect the role of the bone tumor microenvironment and responses to therapies for mCPRC.

Concordance of DNA damage repair (DDR) gene mutations in paired primary and metastatic prostate cancer (PC) samples.

5020 Background: Mutations in DDR genes represent actionable alterations that can be used to guide precision medicine strategies in men with advanced PC. However, acquisition of contemporary tissue samples for advanced molecular testing can be a barrier to deploying precision medicine approaches. We hypothesized that most DDR alterations represent early truncal events in PC and that archival primary tissue would faithfully reflect mutations found in cell-free circulating tumor (ctDNA) and/or metastatic tissue. Methods: Patients were included in this study if a DDR pathway mutation was detected in metastatic tissue or ctDNA and primary tissue sequencing was available for comparison. Sequencing data from three cohorts were analyzed: 1) FoundationOne, 2) University of Washington (UW-OncoPlex or SU2C/PCF International Dream Team sequencing pipelines) and 3) University of Washington rapid autopsy series. Only pathogenic somatic mutations were included and we required ≥30 days between primary tumor tissue and ctDNA/tumor tissue acquisition. Clonal hematopoiesis of indeterminant potential (CHIP) and germline events were adjudicated by an expert molecular pathologist and excluded. Variants detected only in plasma were considered likely to be CHIP or low subclones if the variant fraction was <1% and/or >5-fold less than the estimate tumor content in plasma. Results: Paired primary and ctDNA/metastatic samples were sequenced from 72 individuals with known DDR alterations. After excluding ctDNA cases where only CHIP (N=13) and/or germline events (N=7) were observed, 51 subjects remained and were included in the final analysis. The median time from acquisition of primary tissue to acquisition of ctDNA or tumor tissue was 52 mos (range: 1 – 193 mos). Concordance in DDR genes across samples was 86% (95% CI: 74-93%). Rates of concordance between metastatic-primary and ctDNA-primary pairs were similar when CHIP cases were excluded (87% and 85%, respectively). BRCA2 reversion mutations associated with resistance to PARP inhibitors and platinum chemotherapy were detected in ctDNA from two subjects. Conclusions: These data provide evidence that primary prostate tissue accurately reflect the mutational status of actionable DDR genes in men with metastatic PC, supporting the hypothesis that DDR alterations are early truncal events. After excluding likely CHIP events, ctDNA profiling accurately captured these truncal DDR mutations, while also detecting reversion alterations that may suggest potential resistance mechanisms.[Table: see text]

Comparative study of Hormonal Receptor Status Discrepancy - Brain Breast Cancer Metastasectomy vs Other Localities.

Purpose: Hormonal receptor (HR) status is one of the key factors when determining the treatment of breast cancer. Even though HR conversion is one of the most researched topics recently, most of the previous studies include only the results of biopsies instead of samples obtained by metastasectomy. Aim: The aim of this study is to compare the occurrence of HR status conversion in brain breast cancer metastatic tissue to other localities. Methods: A total of 50 patients after breast cancer metastasectomy of brain, lung or liver were included in the study. The clinical characteristics were recorded. Results: HR conversion was observed in a total of 30 cases (60.0%), while HER2 (human epidermal growth factor receptor 2) discrepancy occurred only in one case (2.0%). Endocrine therapy significantly contributed to the decrease progesterone and estrogen receptor expression in metastatic tissue compared to the primary tumor (p = 0.009, p = 0.023; respectively). Triple negativity was more common in the brain metastases (p = 0.039). Liver metastases occurred in significantly younger patients (p = 0.034), however brain metastases had the poorest OS (p = 0.007). Conclusion: HR conversion occurs in more than 50% of cases of breast cancer metastatic disease, while HER2 discrepancy is rare. Hormonal therapy significantly contributes to the decrease of HR positivity in metastases. Triple negativity is more common in the brain metastases than in other localities. Brain metastases of breast cancer are associated with the poorest prognosis.

Study of association between cancer surface area and histopathological parameters in total laryngectomy specimens

Background/Aim: Numerous histopathological parameters, such as cartilage penetration, perineural and lymphovascular invasion, presence of metastatic tissue in regional lymph nodes, extranodal extension of nodal metastases, as well as presence of cancer tissue on resection borders, are all important factors influencing survival in patients with laryngeal squamous cell carcinoma. A retrospective study was conducted in order to determine association between cancer surface area and these histopathological characteristics. Presence of extranodal extension of metastatic tissue in regional lymph nodes was also investigated. Methods: We revised 140 cases of laryngeal squamous cell carcinoma, processed after total laryngectomy, that were found in archives of Histopathology laboratory of Clinic for Otorhinolaryngology and Maxillofacial Surgery, Clinical Centre of Serbia. Results: A significant difference in cancer surface area was found depending on penetration of thyroid cartilage, perineural invasion and positive resection margins. Cancers with greater surface area were more commonly of higher T stage. Metastases were found in 36 out of 72 neck lymph node samples submitted to evaluation (50%). Difference in cancer surface area was also found depending on presence of metastatic tissue in regional lymph nodes. Extranodal extension was present in 69.4% of involved lymph nodes, and it was more frequent in lymph nodes 3cm in size or larger. Conclusions: There is a significant difference in cancer surface area depending on presence of cartilage penetration, perineural invasion, presence of cancer tissue on resection borders and presence of metastases in regional lymph nodes. Bigger cancers tend to be of a bigger T stage. Extranodal extension is more common in lymph nodes 3cm in size or larger.

Complementary information provided by simultaneous sequencing of CTC, cfDNA and metastatic tissue in endocrine-resistant metastatic breast cancer

Background: Endocrine resistance is a major cause of therapeutic failure in metastatic breast cancer (MBC). The information provided by DNA sequencing of plasma cell free DNA (cfDNA) and by the analysis of circulating tumor cells (CTC) may be useful to determine the occurrence and type of endocrine resistance. However, different levels of concordance between cfDNA and CTC, and also between liquid biopsy and tissue biopsy, have been reported. Thus, the best strategy for performing DNA sequencing in the setting of therapeutic decisions for luminal MBC patients is not well defined. The purpose of this study was to determine the concordance between DNA sequencing data from CTC, cfDNA, metastasis, and primary tumor in endocrine-resistant luminal MBC.Methods: Using the same panel (10 genes) we performed simultaneous sequencing of cfDNA, CTC, metastases and primary tumor in 38 patients with luminal MBC. CTC isolation was performed with an Epcam-based immunomagnetic system. Concordance of DNA sequencing data of the different types of sample was analyzed and correlated with clinical data. Results: CTC were detected in 21% of the patients. The rate of detection of genetic alterations was 87.5% for CTC, 61.5% for cfDNA, 63.2% for metastasis and 67.7% for primary tumor, and involved mainly TP53, PIK3CA, ESR1 and AKT1. A higher number of mutations was found in cfDNA of MBC patients with progressive disease (p=0.02) and the same trend was observed for endocrine resistance (p=0.08), especially for PIK3CA, ESR1 and AKT1 mutations. Global concordance was low to intermediate between CTC and cfDNA, but significantly higher between CTC and metastasis. Concordance also varied according to the specific genetic alteration, with no ESR1 mutations detected in CTC and with a low concordance for PIK3CA and AKT1 mutations between CTC and cfDNA samples.Conclusions: DNA sequencing of different types of tumor samples (cfDNA, CTC, metastasis and primary tumor) may provide different rates of genomic alterations detection in luminal endocrine-resistant MBC. A moderate to low concordance, with discordances depending both on the clinical situation and on the sequenced gene, support the complementarity of the different samples, with cfDNA and metastatic tissue as the preferred sources of tumor DNA.