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Purpose Multi-gene signatures provide biological insight and risk stratification in breast cancer. Intrinsic molecular subtypes defined by mRNA expression of 50 genes (PAM50) are prognostic in hormone-receptor positive postmenopausal breast cancer. Yet, for 25–40% in the PAM50 intermediate risk group, long-term risk remains uncertain. Our study aimed to (i) test the long-term prognostic value of the PAM50 signature in pre- and post-menopausal breast cancer; (ii) investigate if the PAM50 model could be improved by addition of other mRNAs implicated in oncogenesis. Methods We used archived FFPE samples from 1723 breast cancer survivors; high quality reads were obtained on 1253 samples. Transcript expression was quantified using a custom codeset with probes for > 100 targets. Cox models assessed gene signatures for breast cancer relapse and survival. Results Over 15 + years of follow-up, PAM50 subtypes were ( P  < 0.01) associated with breast cancer outcomes after accounting for tumor stage, grade and age at diagnosis. Results did not differ by menopausal status at diagnosis. Women with Luminal B (versus Luminal A) subtype had a > 60% higher hazard. Addition of a 13-gene hypoxia signature improved prognostication with > 40% higher hazard in the highest vs lowest hypoxia tertiles. Conclusions PAM50 intrinsic subtypes were independently prognostic for long-term breast cancer survival, irrespective of menopausal status. Addition of hypoxia signatures improved risk prediction. If replicated, incorporating the 13-gene hypoxia signature into the existing PAM50 risk assessment tool, may refine risk stratification and further clarify treatment for breast cancer.

PAM50 intrinsic breast cancer subtypes are prognostic independent of standard clinicopathologic factors. CALGB 9741 demonstrated improved recurrence-free (RFS) and overall survival (OS) with 2-weekly dose-dense (DD) versus 3-weekly therapy. A significant interaction between intrinsic subtypes and DD-therapy benefit was hypothesized. Suitable tumor samples were available from 1,471 (73%) of 2,005 subjects. Multiplexed gene-expression profiling generated the PAM50 subtype call, proliferation score, and risk of recurrence score (ROR-PT) for the evaluable subset of 1,311 treated patients. The interaction between DD-therapy benefit and intrinsic subtype was tested in a Cox proportional hazards model using two-sided alpha=0.05. Additional multivariable Cox models evaluated the proliferation and ROR-PT scores as continuous measures with selected clinical covariates. Improved outcomes for DD therapy in the evaluable subset mirrored results from the complete data set (RFS; hazard ratio=1.20; 95% confidence interval=0.99–1.44) with 12.3-year median follow-up. Intrinsic subtypes were prognostic of RFS ( P <0.0001) irrespective of treatment assignment. No subtype-specific treatment effect on RFS was identified (interaction P =0.44). Proliferation and ROR-PT scores were prognostic for RFS (both P <0.0001), but no association with treatment benefit was seen ( P =0.14 and 0.59, respectively). Results were similar for OS. The prognostic value of PAM50 intrinsic subtype was greater than estrogen receptor/HER2 immunohistochemistry classification. PAM50 gene signatures were highly prognostic but did not predict for improved outcomes with DD anthracycline- and taxane-based therapy. Clinical validation studies will assess the ability of PAM50 and other gene signatures to stratify patients and individualize treatment based on expected risks of distant recurrence. Genomic testing: Predictive power of multigene activity Testing the activity of a set of 50 genes predicts breast cancer outcomes, but requires further validation as a tool to guide treatment. Minetta Liu of the Mayo Clinic in Minnesota, United States, together with US and Canadian colleagues, assessed the predictive power of the PAM50 genomic test for breast cancer. They analyzed tumor samples taken from 1,471 patients more than 12 years ago, comparing their results with knowledge of subsequent clinical outcomes and relapse. The team found that while specific PAM50 gene activity signatures were highly predictive of disease outcome and the incidence of relapse, PAM50 test results did not indicate the likelihood of improved outcomes with 2-weekly dose dense anthracycline and taxane-based chemotherapy. Predicting the benefit of different therapeutic strategies therefore remains a challenge. Future studies should investigate the potential of PAM50 testing for guiding chemotherapy choices.

Tubular carcinoma (TC) is a rare, luminal A subtype of breast carcinoma with excellent prognosis, for which adjuvant chemotherapy is usually contraindicated. To examine the levels of estrogen receptor (ER) and progesterone receptor expression in cases of TC and well-differentiated invasive ductal carcinoma as compared to normal breast glands and to determine if any significant differences could be detected via molecular testing. We examined ER and progesterone receptor via immunohistochemistry in tubular (N = 27), mixed ductal/tubular (N = 16), and well-differentiated ductal (N = 27) carcinomas with comparison to surrounding normal breast tissue. We additionally performed molecular subtyping of 10 TCs and 10 ductal carcinomas via the PAM50 assay. Although ER expression was high for all groups, TC had statistically significantly lower ER staining percentage (ER%) (P = .003) and difference in ER expression between tumor and accompanying normal tissue (P = .02) than well-differentiated ductal carcinomas, with mixed ductal/tubular carcinomas falling between these 2 groups. Mean ER% was 79%, 87%, and 94%, and mean tumor-normal ER% differences were 13.6%, 25.9%, and 32.6% in tubular, mixed, and ductal carcinomas, respectively. Most tumors that had molecular subtyping were luminal A (9 of 10 tubular and 8 of 10 ductal), and no significant differences in specific gene expression between the 2 groups were identified. Tubular carcinoma exhibited decreased intensity in ER expression, closer to that of normal breast parenchyma, likely as a consequence of a high degree of differentiation. Lower ER% expression by TC may represent a potential pitfall when performing commercially available breast carcinoma prognostic assays that rely heavily on ER-related gene expression.

The sequencing of AML genomes of eight patients before and after relapse reveals two major patterns of clonal evolution, with chemotherapy appearing to have a role in both patterns. Tumour cell evolution in AML Many patients with acute myeloid leukaemia (AML) achieve remission, but it is often short-lived and the returned disease is usually refractory to therapy. Genome sequencing of eight patients with AML before and after relapse reveals two major patterns of tumour cell evolution. The founding clone survives chemotherapy in all patients, and, in one clonal pattern, it acquires new mutations and expands at relapse. In the other, a subclone surviving from the original tumour expands and then acquires new mutations. Comparisons of relapse-specific and primary tumour mutations point to an increase in transversions, implying DNA damage caused by cytotoxic chemotherapy. This work demonstrates that the AML genome in an individual patient presents a moving target, and highlights the importance of striving to eradicate both the founding clone and all of its subclones. Most patients with acute myeloid leukaemia (AML) die from progressive disease after relapse, which is associated with clonal evolution at the cytogenetic level 1 , 2 . To determine the mutational spectrum associated with relapse, we sequenced the primary tumour and relapse genomes from eight AML patients, and validated hundreds of somatic mutations using deep sequencing; this allowed us to define clonality and clonal evolution patterns precisely at relapse. In addition to discovering novel, recurrently mutated genes (for example, WAC , SMC3 , DIS3 , DDX41 and DAXX ) in AML, we also found two major clonal evolution patterns during AML relapse: (1) the founding clone in the primary tumour gained mutations and evolved into the relapse clone, or (2) a subclone of the founding clone survived initial therapy, gained additional mutations and expanded at relapse. In all cases, chemotherapy failed to eradicate the founding clone. The comparison of relapse-specific versus primary tumour mutations in all eight cases revealed an increase in transversions, probably due to DNA damage caused by cytotoxic chemotherapy. These data demonstrate that AML relapse is associated with the addition of new mutations and clonal evolution, which is shaped, in part, by the chemotherapy that the patients receive to establish and maintain remissions.

To correlate the variable clinical features of oestrogen-receptor-positive breast cancer with somatic alterations, we studied pretreatment tumour biopsies accrued from patients in two studies of neoadjuvant aromatase inhibitor therapy by massively parallel sequencing and analysis. Eighteen significantly mutated genes were identified, including five genes ( RUNX1 , CBFB , MYH9 , MLL3 and SF3B1 ) previously linked to haematopoietic disorders. Mutant MAP3K1 was associated with luminal A status, low-grade histology and low proliferation rates, whereas mutant TP53 was associated with the opposite pattern. Moreover, mutant GATA3 correlated with suppression of proliferation upon aromatase inhibitor treatment. Pathway analysis demonstrated that mutations in MAP2K4 , a MAP3K1 substrate, produced similar perturbations as MAP3K1 loss. Distinct phenotypes in oestrogen-receptor-positive breast cancer are associated with specific patterns of somatic mutations that map into cellular pathways linked to tumour biology, but most recurrent mutations are relatively infrequent. Prospective clinical trials based on these findings will require comprehensive genome sequencing. Whole-genome analysis of oestrogen-receptor-positive tumours in patients treated with aromatase inhibitors show that distinct phenotypes are associated with specific patterns of somatic mutations; however, most recurrent mutations are relatively infrequent so prospective clinical trials will require comprehensive sequencing and large study populations. Tumour responsiveness to aromatase inhibitors Elaine Mardis and colleagues use whole-genome sequencing to gain insight into the mutational landscape of tissue samples from patients with oestrogen-receptor-positive (ER+) breast cancer treated with a neoadjuvant aromatase inhibitor. They identify a number of disease-linked mutations that specifically correlate with tumour-cell histology, proliferation rates and response to treatment. Such information could be used to determine which patients will benefit from aromatase-inhibitor therapy.

Whole-genome sequence analysis of cells from a patient with acute myeloid leukemia (AML) revealed a mutation in DNMT3A, which encodes an enzyme that methylates DNA. Subsequent analyses showed that DNMT3A was mutated in 33.7% of patients with AML with an intermediate-risk cytogenetic profile. Whole-genome sequencing is an unbiased approach for discovering somatic variations in cancer genomes. We recently reported the DNA sequence and analysis of the genomes of two patients with acute myeloid leukemia (AML) with a normal karyotype. 1 , 2 We did not find new recurring mutations in the first study but did observe a recurrent mutation in IDH1, encoding isocitrate dehydrogenase 1, in the second study. 2 Subsequent work has confirmed and extended this finding, showing that mutations in IDH1 and related gene IDH2 are highly recurrent in patients with an intermediate-risk cytogenetic profile (20 to 30% frequency) and are associated with a . . .

Massively parallel DNA sequencing technologies provide an unprecedented ability to screen entire genomes for genetic changes associated with tumour progression. Here we describe the genomic analyses of four DNA samples from an African-American patient with basal-like breast cancer: peripheral blood, the primary tumour, a brain metastasis and a xenograft derived from the primary tumour. The metastasis contained two de novo mutations and a large deletion not present in the primary tumour, and was significantly enriched for 20 shared mutations. The xenograft retained all primary tumour mutations and displayed a mutation enrichment pattern that resembled the metastasis. Two overlapping large deletions, encompassing CTNNA1 , were present in all three tumour samples. The differential mutation frequencies and structural variation patterns in metastasis and xenograft compared with the primary tumour indicate that secondary tumours may arise from a minority of cells within the primary tumour. Cancer progression genomics With the latest DNA sequencing technologies it is now possible to screen an entire genome for the genetic changes associated with tumour progression. This approach has been used to obtain complete sequences of four DNA samples from a 44-year-old African-American patient with basal-like breast cancer: the primary tumour, peripheral blood, a brain metastasis and a first-passage xenograft derived from the primary tumour. Mutational analysis suggests that the metastasis tumour specifically selects a subset of cells from the primary tumour that contain pre-existing mutations, and also develops a small number of de novo mutations. Massively parallel DNA sequencing allows entire genomes to be screened for genetic changes associated with tumour progression. Here, the genomes of four DNA samples from a 44-year-old African-American patient with basal-like breast cancer were analysed. The samples came from peripheral blood, the primary tumour, a brain metastasis and a xenograft derived from the primary tumour. The findings indicate that cells with a distinct subset of the primary tumour mutation might be selected during metastasis and xenografting.

A comparison of the genomic sequence of a tumor sample from a patient with acute myeloid leukemia (AML) and that of a normal skin sample from the same patient revealed an estimated 750 somatic mutations, of which 12 were in the coding sequences of genes and 52 were in conserved regions or regions with regulatory potential. Four mutations were found to be recurrent in AML, including mutations in NRAS, NPM1, IDH1, and a conserved region on chromosome 10. A comparison of the genomic sequence of a tumor sample from a patient with acute myeloid leukemia (AML) and that of a normal skin sample from the same patient revealed an estimated 750 somatic mutations. Four mutations were found to be recurrent in AML. Acute myeloid leukemia (AML) is a clonal hematopoietic disease caused by both inherited and acquired genetic alterations. 1 – 3 Current AML classification and prognostic systems incorporate genetic information but are limited to known abnormalities that have previously been identified with the use of cytogenetics, array comparative genomic hybridization (CGH), gene-expression profiling, and the resequencing of candidate genes (see the Glossary). The karyotyping of AML cells remains the most powerful predictor of the outcome in patients with AML and is routinely used by clinicians. 4 , 5 As an adjunct to cytogenetic studies, small subcytogenetic amplifications and deletions can be identified with the use . . .

To investigate the genetic changes associated withAML relapse, and to determine whether clonal evolution contributes to relapse, we performed whole-genome sequencing of primary tumour-relapse pairs andmatched skin samples fromeight patients, including unique patient identifier (UPN) 933124, whose primary tumourmutations were previously reported3. Assuming that all the mutations detected are heterozygous in the primary tumour sample (with a malignant cellular content at 93.72% for the primary bone marrow sample, see Supplementary Information), we were able to calculate the fraction of total malignant cells in each clone.

Most patients with acute myeloid leukaemia (AML) die from progressive disease after relapse, which is associated with clonal evolution at the cytogenetic level (1,2). To determine the mutational spectrum associated with relapse, we sequenced the primary tumour and relapse genomes from eight AML patients, and validated hundreds of somatic mutations using deep sequencing; this allowed us to define clonality and clonal evolution patterns precisely at relapse. In addition to discovering novel, recurrently mutated genes (for example, WAC, SMC3, DIS3, DDX41 and DAXX) in AML, we also found two major clonal evolution patterns during AML relapse: (1) the founding clone in the primary tumour gained mutations and evolved into the relapse clone, or (2) a subclone of the founding clone survived initial therapy, gained additional mutations and expanded at relapse. In all cases, chemotherapy failed to eradicate the founding clone. The comparison of relapse-specific versus primary tumour mutations in all eight cases revealed an increase in transversions, probably due to DNA damage caused by cytotoxic chemotherapy. These data demonstrate that AML relapse is associated with the addition of new mutations and clonal evolution, which is shaped, in part, by the chemotherapy that the patients receive to establish and maintain remissions.