Modulation of stress and immune response by Amblyomin-X results in tumor cell death in a horse melanoma model

We have investigated Amblyomin-X-treated horse melanomas to better understand its mode of action through transcriptome analysis and the in vivo model. Amblyomin-X is a Kunitz-type homologous protein that selectively leads to the death of tumor cells via ER stress and apoptosis, currently under investigation as a new drug candidate for cancer treatment. Melanomas are immunogenic tumors, and a better understanding of the immune responses is warranted. Equine melanomas are spontaneous and not so aggressive as human melanomas are, as this study shows that the in vivo treatment of encapsulated horse melanoma tumors led to a significant reduction in the tumor size or even the complete disappearance of the tumor mass through intratumoral injections of Amblyomin-X. Transcriptome analysis identified ER- and mitochondria-stress, modulation of the innate immune system, apoptosis, and possibly immunogenic cell death activation. Interactome analysis showed that Amblyomin-X potentially interacts with key elements found in transcriptomics. Taken together, Amblyomin-X modulated the tumor immune microenvironment in different ways, at least contributing to induce tumor cell death.

Abstract P4-01-09: Combined analysis of tissue and blood biopsies by NGS in patients with advanced breast cancer identifies targetable molecular alterations

Background: Targeted-next generation sequencing (t-NGS) analysis in tissue and peripheral blood is increasingly performed in patients with advanced cancer. Liquid biopsy is a non-invasive method that allows to understand the molecular changes occurring in the tumor in real-time, derived from intratumor heterogeneity and/or therapeutic pressure. In the present work we sought to elucidate the ability of liquid biopsy to detect mutations related with acquired resistance.

Methods: 190 formalin-fixed paraffin-embedded (FFPE) samples from primary and metastatic tumors of patients with advanced breast cancer (ABC) were analyzed by OncoDEEP® (1000X depth of coverage of 75 gene alterations including point mutations, insertions/deletions, gene fusions and copy number variations), and comparison between targeted-NGS results from matched primary/metastatic tumors (FFPE) and cell-free DNA (cfDNA) recovery from plasma analyzed by OncoSTRAT&GO® in 34 patients with ABC (193 genes with 1000x and 40 genes with 10000x depth coverage for FFPE and plasma, respectively).

Results: Of the 190 FFPEs analyzed by OncoDEEP®, 41% were triple negative breast cancer (TNBC), 49% hormone receptor positive (HR+) and 11% were HER2+. Mutations in TP53 (44.2%), PIK3CA (41.1%) and ERBB2 (9.47%) were the most frequent. As expected, PIK3CA and TP53 mutations were significantly higher in HR+ and TNBC tumors, respectively (PIK3CA: 53.8% for HR+ vs 28.6% and 30% for TNBC and HER2+, respectively; TP53 68.8% for TNBC vs 26.9 and 30% in HR+ and HER2+, respectively; in both cases p<0.001). Interestingly, the alteration c.1459-7C>T in JAK1 (unknown significance) was detected in 8% of patients (9.7% and 6.5% in HR+ and TNBC, respectively). Also, in contrast to other reports, high frequencies of APC alterations were found exclusively in HR+ tumors (previously reported as germline mutations). From the OncoSTRAT&GO® analysis (tumor tissue and cfDNA), ESR1 and FGFR mutations in HR+ ABC were significantly more present in cfDNA (9/20 mutations found [45%]] compared to tumor tissue analysis (18/93 mutations found [19.3%]) (p=0.02), and in three patients, mutations in ESR1 and FGRF were only detected in cfDNA. Finally, 11/34 cases (32.3%) showed gene mutations only in cfDNA with predominant alterations in MAPK signaling pathway (54.5%), TP53 (36.4%) and ESR1 (18.2%), the latest as previously described.

Conclusions: JAK1 and APC mutations need further evaluation to establish their clinical significance in ABC. The combination of tumor tissue and cfDNA t-NGS analyses into clinical routine enables detailed and comprehensive evaluation of tumor heterogeneity under therapeutic pressure; in our cohort, known mutations for acquired resistance to endocrine therapy (ESR1 and FGFR2) were better detected by cfDNA compared to tumor tissue (45% vs 19.3%) in HR+ ABC patients, increasing the probability to identify early drug resistance to prioritize patients' selection into clinical trials with targeted agents.

Citation Format: Salvador JF, Pinto JA, Araujo JM, Tirado-Hurtado I, Flores CJ, Chirinos LA, Requena MC, Carpio S, Finzel Pérez A, Aguilar A, Demol F, Schwarz LJ. Combined analysis of tissue and blood biopsies by NGS in patients with advanced breast cancer identifies targetable molecular alterations [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-01-09.

Abstract P5-09-08: Molecular evaluation of Peruvian patients with hereditary breast cancer reveals a novel germline mutation in BRCA1

Background

Breast cancer is the leading cancer in women worldwide, while in Peru is the second most frequent cancer with a high incidence of triple negative breast cancers (21%). There is no previous information about BRCA1/BRCA2 mutations in Peruvian high-risk breast cancer patients. Prior studies from International diagnostic laboratories only presented results of our population as a pooled Hispanic data. Our aim was to characterize mutations in BRCA1/BRCA2 genes in Peruvian patients with breast cancer with hereditary patterns.

Methods

We evaluated mutations in BRCA1/BRCA2 genes by Sanger sequencing and large genomic rearrangements by multiplex ligation-dependent probe amplification (MLPA) in 18 families with hereditary breast cancer criteria identified at the Breast Unit of Oncosalud-AUNA (Lima-Peru). Molecular analysis was done in the facilities of Genetics and Molecular Biology Center at the San Martin de Porres University (Lima-Peru).

Results

Sequencing identified 4 pathogenic mutations in 4/18 families, three previously detected (BRCA1: c.302-1G>C y c.815_824dup10; BRCA2: c.5946delT) and a novel germline mutation in exon 15 of BRCA1 (c.4647_4648dupAA, ClinVar SCV000256598.1) producing a frameshift variant. MLPA revealed 2 amplifications in exon 7 (duplication and triplication) in BRCA1 in unrelated patients with potential pathogenic effects, one of this co-existed with the BRCA2: c.5946delT mutation. In addition, three variants of uncertain significance were found (c.140G>T, in exon 5 of BRCA1 and c.464G>A and c.938C>T in exon 5 and 10 of BRCA2, respectively).

Conclusions

After a comprehensive evaluation we found an alteration rate of 27.8% (5/18) in BRCA1/BRCA2 in families with criteria for hereditary breast cancer. We reported BRCA1 c.4647_4648dupAA as a novel mutation. Further studies including a larger sample size of Peruvian patients should evaluate the prevalence or founder effect of this mutation in our population.

Citation Format: Ponce J, Vigil C, Araujo JM, Castañeda C, Calderon G, Buleje JL, Acosta O, Danos P, Huaman F, Guevara-Fujita ML, Aguilar A, Pinto JA, Gomez HL, Fujita R. Molecular evaluation of Peruvian patients with hereditary breast cancer reveals a novel germline mutation in BRCA1 [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-09-08.

Decreased point prevalence of Haemophilus influenzae type b (Hib) oropharyngeal colonization by mass immunization of Brazilian children less than 5 years old with hib polyribosylribitol phosphate polysaccharide-tetanus toxoid conjugate vaccine in combination with diphtheria-tetanus toxoids-pertussis vaccine

A protective herd effect has been described after susceptible populations of children are vaccinated with conjugate Haemophilus influenzae type b (Hib). Hib carriage was studied in children aged 6-24 months attending day care centers in two cities in southern Brazil (Curitiba and Porto Alegre). In Curitiba, routine immunization with Hib polyribosylribitol phosphate polysaccharide-tetanus toxoid conjugate vaccine (PRP-T) in combination with diphtheria-tetanus toxoids-pertussis vaccine (PRP-T/DTP) has been offered since September 1996; DTP vaccine alone is routinely given in Porto Alegre. Children in Porto Alegre (n=643) were 8 times less likely to have received adequate Hib vaccination and 4 times more likely to be Hib carriers than children in Curitiba (n=647; i.e., point prevalence of oropharyngeal colonization, 4.8% vs. 1.2%). Point prevalence of carriage with non-type b or other nontypeable Hi was similar in children of both cities. There was a vaccination effect on carriage rates in children who received a primary 3-dose series, independent of the booster dose, suggesting that a booster may be unnecessary to induce population protection.