A Four-gene Decision Tree Signature Classification of Triple-negative Breast Cancer: Implications for Targeted Therapeutics
MOLECULAR CANCER THERAPEUTICS
Authors: Quist, Jelmar; Mirza, Hasan; Cheang, Maggie C. U.; Telli, Melinda L.; O'Shaughnessy, Joyce A.; Lord, Christopher J.; Tutt, Andrew N. J.; Grigoriadis, Anita
Abstract
The molecular complexity of triple-negative breast cancers (TNBCs) provides a challenge for patient management. We set out to characterize this heterogeneous disease by combining transcriptomics and genomics data, with the aim of revealing convergent pathway dependencies with the potential for treatment intervention. A Bayesian algorithm was used to integrate molecular profiles in two TNBC cohorts, followed by validation using five independent cohorts (n = 1,168), including three clinical trials. A four-gene decision tree signature was identified, which robustly classified TNBCs into six subtypes. All four genes in the signature (EXO1, TP53BP2, FOXM1, and RSU1) are associated with either genomic instability, malignant growth, or treatment response. One of the six subtypes, MC6, encompassed the largest proportion of tumors (similar to 50%) in early diagnosed TNBCs. In TNBC patients with metastatic disease, the MC6 proportion was reduced to 25%, and was independently associated with a higher response rate to platinum-based chemotherapy. In TNBC cell line data, platinum sensitivity was recapitulated, and a sensitivity to the inhibition of the phosphatase PPM1D was revealed. Molecularly, MC6-TNBCs displayed high levels of telomeric allelic imbalances, enrichment of CD4(+) and CD8(+) immune signatures, and reduced expression of genes negatively regulating the MAPK signaling pathway. These observations suggest that our integrative classification approach may identify TNBC patients with discernible and theoretically pharmacologically tractable features that merit further studies in prospective trials.
Novel TG-FGFR1 and TRIM33-NTRK1 transcript fusions in papillary thyroid carcinoma
GENES CHROMOSOMES & CANCER
Authors: Pfeifer, Aleksandra; Rusinek, Dagmara; Zebracka-Gala, Jadwiga; Czarniecka, Agnieszka; Chmielik, Ewa; Zembala-Nozynska, Ewa; Wojtas, Bartosz; Gielniewski, Bartlomiej; Szpak-Ulczok, Sylwia; Oczko-Wojciechowska, Malgorzata; Krajewska, Jolanta; Polanska, Joanna; Jarzab, Barbara
Abstract
Papillary thyroid carcinoma (PTC) is most common among all thyroid cancers. Multiple genomic alterations occur in PTC, and gene rearrangements are one of them. Here we screened 14 tumors for novel fusion transcripts by RNA-Seq. Two samples harboring RET/PTC1 and RET/PTC3 rearrangements were positive controls whereas the remaining ones were negative regarding the common PTC alterations. We used Sanger sequencing to validate potential fusions. We detected 2 novel potentially oncogenic transcript fusions: TG-FGFR1 and TRIM33-NTRK1. We detected 4 novel fusion transcripts of unknown significance accompanying the TRIM33-NTRK1 fusion: ZSWIM5-TP53BP2, TAF4B-WDR1, ABI2-MTA3, and ARID1B-PSMA1. Apart from confirming the presence of RET/PTC1 and RET/PTC3 in positive control samples, we also detected known oncogenic fusion transcripts in remaining samples: TFG-NTRK1, ETV6-NTRK3, MKRN1-BRAF, EML4-ALK, and novel isoform of CCDC6-RET.