Variant analysis of prostate cancer in Japanese patients and a new attempt to predict related biological pathways.
There are regional and/or ethnic differences in tumorigenic pathways among several types of cancer, including prostate cancer (PCa). However, information on genome‑wide gene alterations and the transcriptome is currently only available for PCa patients from Western countries. In order to profile the genetic alterations in Japanese patients with PCa, new panels were created to examine nucleotide sequence variations in 71 selected PCa‑related genes (KCC71) and to detect all fusion RNA transcripts known in PCa (PCaFusion). An analysis of 21 Japanese PCa cases identified 33 different somatic variants in 24 genes in the KCC71 panel, including 2 in SPOP (F102V and F133L), 2 in BRCA2 (I1859fs and R2318ter, resulting in premature termination of the polypeptide), and 1 each in BRAF (K601E), CDH1 (E880K) and RB1 (R621S), as pathogenic alterations. Unexpectedly, the TMPRSS2‑ERG fusion transcript was detected in only 1 case, although the SLC45A3‑ELK4 and USP9Y‑TTTY15 fusion transcripts, known as transcription‑mediated chimeric RNAs, were detected in all examined cases. A new pathway analysis with The Cancer Network Galaxy (TCNG), a cancer gene regulatory network database, was also applied in an attempt to predict molecular pathways implicated in PCa in the Japanese population. Based on the 24 genes having somatic variants identified by the panel analysis as initial seed genes, a putative core network was finally established, including 5 identified genes, namely TNK2, SOX9, CDH1, FOXA1 and TP53, with high commonality from TCNG datasets. These genes are expected to be involved in tumor development, as revealed by the results of an enrichment analysis with Gene Ontology terms. This analysis must be further extended to include more cases in order to verify this method and also to elucidate the characteristics of PCa in Japanese patients.
Publication Date: 2020-02-06
Journal: Oncology reports
Integration of Comprehensive Genomic Analysis and Functional Screening of Affected Molecular Pathways to Inform Cancer Therapy.
To select optimal therapies based on the detection of actionable genomic alterations in tumor samples is a major challenge in precision medicine.
We describe an effective process (opened December 1, 2017) that combines comprehensive genomic and transcriptomic tumor profiling, custom algorithms and visualization software for data integration, and preclinical 3-dimensiona ex vivo models for drug screening to assess response to therapeutic agents targeting specific genomic alterations. The process was applied to a patient with widely metastatic, weakly hormone receptor positive, HER2 nonamplified, infiltrating lobular breast cancer refractory to standard therapy.
Clinical testing of liver metastasis identified BRIP1, NF1, CDH1, RB1, and TP53 mutations pointing to potential therapies including PARP, MEK/RAF, and CDK inhibitors. The comprehensive genomic analysis identified 395 mutations and several structural rearrangements that resulted in loss of function of 36 genes. Meta-analysis revealed biallelic inactivation of TP53, CDH1, FOXA1, and NIN, whereas only one allele of NF1 and BRIP1 was mutated. A novel ERBB2 somatic mutation of undetermined significance (P702L), high expression of both mutated and wild-type ERBB2 transcripts, high expression of ERBB3, and a LITAF-BCAR4 fusion resulting in BCAR4 overexpression pointed toward ERBB-related therapies. Ex vivo analysis validated the ERBB-related therapies and invalidated therapies targeting mutations in BRIP1 and NF1. Systemic patient therapy with afatinib, a HER1/HER2/HER4 small molecule inhibitor, resulted in a near complete radiographic response by 3 months.
Unlike clinical testing, the combination of tumor profiling, data integration, and functional validation accurately assessed driver alterations and predicted effective treatment.
Publication Date: 2019-11-07
Journal: Mayo Clinic proceedings