The Evolution of Clinically Aggressive Triple-Negative Breast Cancer Shows a Large Mutational Diversity and Early Metastasis to Lymph Nodes

Abstract

In triple-negative breast cancer (TNBC), only 30% of patients treated with neoadjuvant chemotherapy achieve a pathological complete response after treatment and more than 90% die due to metastasis formation. The diverse clinical responses and metastatic developments are attributed to extensive intrapatient genetic heterogeneity and tumor evolution acting on this neoplasm. In this work, we aimed to evaluate genomic alterations and tumor evolution in TNBC patients with aggressive disease. We sequenced the whole exome of 16 lesions from four patients who did not respond to therapy, and took several follow-up samples, including samples from tumors before and after treatment, as well as from the lymph nodes and skin metastases. We found substantial intrapatient genetic heterogeneity, with a variable tumor mutational composition. Early truncal events were MCL1 amplifications. Metastatic lesions had deletions in RB1 and PTEN, along with TERT, AKT2, and CCNE1 amplifications. Mutational signatures 06 and 12 were mainly detected in skin metastases and lymph nodes. According to phylogenetic analysis, the lymph node metastases occurred at an early stage of TNBC development. Finally, each patient had three to eight candidate driving mutations for targeted treatments. This study delves into the genomic complexity and the phylogenetic and evolutionary development of aggressive TNBC, supporting early metastatic development, and identifies specific genetic alterations associated with a response to targeted therapies.

Regulation and clinical potential of telomerase reverse transcriptase (TERT/hTERT) in breast cancer

“…In metastases from patients with triple-negative breast cancer, hTERT amplification has been detected, along with amplifications of AKT2 and CCNE1 [ 125 ]. Moreover, hTERT promoter hotspot mutations and gene amplification have been identified in malignant breast cancers with predominantly non-chondroid components, accounting for 17% of cases [ 18 ].…”

Mutational spectrum of breast cancer by shallow whole-genome sequencing of cfDNA and tumor gene panel analysis

“…Bioinformatic analyses were performed using previously described methods 41,42 . Briefly, BWA 43 and GATK 44 were used for alignment and data processing, respectively.…”

Magnetic Resonance Diagnosis of Early Triple-Negative Breast Cancer Based on the Ionic Covalent Organic Framework with High Relaxivity and Long Retention Time

“…Lymph node (LN) metastasis constitutes a critical independent risk factor and is strongly linked to poor TNBC prognosis and increased chance of recurrence. − At the time of initial diagnosis, TNBC patients are more prone to suffer from LN metastasis compared to other BC subtypes. , Surgeons must determine whether metastases occur in LNs or not, since excessive dissection of normal LNs might expose patients to unnecessary risks . LN biopsy has been considered a gold standard for diagnosing lymphatic metastasis; − however, it is invasive and lacks accuracy while being limited by lymph node sampling’s operating sites.…”