Comutation of PIK3CA and TP53 in Residual Disease After Preoperative Anti-HER2 Therapy in ERBB2 (HER2)-Amplified Early Breast Cancer.

PURPOSE: To identify proteomic and genomic alterations in residual disease (RD) for human epidermal growth factor receptor 2 (HER2)-positive (HER2+) breast cancer (BC) after preoperative trastuzumab (H), lapatinib (L), or both (H+L) in combination with chemotherapy. PATIENTS AND METHODS: Patients with stage II/III HER2+ BC (n = 100) were randomly assigned to preoperative treatment with H versus L 1,250mg versus H+L (L: 750 to 1,000 mg) plus 5-fluorouracil, epirubicin, and cyclophosphamide, followed by weekly paclitaxel. After receiving institutional review board-approved informed consent, targeted next-generation sequencing was performed on 20 patients' formalin-fixed paraffin embedded tumors to characterize genomic alterations across 287 cancer-related genes. Reverse phase protein array (RPPA) analysis was performed on both the baseline biopsy and RD specimens, when available. RESULTS: Two of 20 RD tissues were HER2 negative per next-generation sequencing; one sample had insufficient tissue. Of six pretreatment biopsy specimens, four were comutated with TP53 and PIK3CA. Of 17 HER2+ RD, seven specimens (41%) had PIK3CA mutations always comutated with TP53, and four (24%) also had concurrent CDK12 amplification. Overall, CDK12 amplification was observed in eight of the 17 (47%) HER2+ RD specimens. A total of 12 RD specimens (71%) had TP53 mutations. Although prevalence of individual TP53 and PIK3CA mutations was only modestly higher than published estimates for those in HER2+ primary BCs (55% and 32% for TP53 and PIK3CA, respectively), prevalence of these as comutations appeared higher (41%), compared with less than 10% in several series. On RPPA analysis of the RD tissue with comutations, the strongest Spearman ρ correlations were limited to EGFR and phospho-AKT (ρ, 0.999; P = .019) and phospho-mTOR and phospho-S6 ribosomal protein (ρ, 0.994; P = .048). CONCLUSION: HER2-amplified RD tissue after preoperative H, L, or H+L plus chemotherapy was enriched for PIK3CA and TP53 comutations, and the RD tissue demonstrated activation of EGFR/AKT/mTOR signaling on RPPA.

Distinct age-associated molecular profiles in acute myeloid leukemia defined by comprehensive clinical genomic profiling.

Large scale comprehensive genomic profiling (CGP) has led to an improved understanding of oncogenic mutations in acute myeloid leukemia (AML), as well as identification of alterations that can serve as targets for potential therapeutic intervention. We sought to gain insight into age-associated variants in AML through comparison of extensive DNA and RNA-based GP results from pediatric and adult AML. Sequencing of 932 AML specimens (179 pediatric (age 0-18), 753 adult (age ≥ 19)) from diagnostic, relapsed, and refractory times points was performed. Comprehensive DNA (405 genes) and RNA (265) sequencing to identify a variety of structural and short variants was performed. We found that structural variants were highly prevalent in the pediatric cohort compared to the adult cohort (57% vs. 30%; p < 0.001), with certain structural variants detected only in the pediatric cohort. Fusions were the most common structural variant and were highly prevalent in AML in very young children occurring in 68% of children < 2 years of age. We observed an inverse trend in the prevalence of fusions compared to the average number of mutations per patient. In contrast to pediatric AML, adult AML was marked by short variants and multiple mutations per patient. Mutations that were common in adult AML were much less common in the adolescent and young adult cohort and were rare or absent in the pediatric cohort. Clinical CGP demonstrates the biologic differences in pediatric vs. adult AML that have significant therapeutic impacts on prognosis, therapeutic allocation, disease monitoring, and the use of more targeted therapies.

BRAF internal deletions and resistance to BRAF/MEK inhibitor therapy.

BRAF and MEK inhibitors have improved clinical outcomes in advanced, BRAFV600 -mutated melanomas. Acquired resistance occurs in most patients, with numerous and diverse drivers. We obtained pretreatment and progression biopsies from a patient who progressed on dabrafenib and trametinib. In addition to a preserved BRAFV600E mutation, an internal deletion (rearrangement) of BRAF was observed in the progression sample. This deletion involved exons 2-8, which includes the Ras-binding domain, and is analogous to previously documented BRAF fusions and splice variants known to reactivate RAS-RAF-MEK-ERK signaling. In a large cohort of melanomas, 10 additional internal deletions were identified (0.4% of all melanomas; nine of which had concurrent BRAF mutations), as well as sporadically in other tumor types. Thus, we describe a novel mechanism of resistance to BRAF and MEK inhibition.

Genomics of primary chemoresistance and remission induction failure in paediatric and adult acute myeloid leukaemia.

Cure rates of children and adults with acute myeloid leukaemia (AML) remain unsatisfactory partly due to chemotherapy resistance. We investigated the genetic basis of AML in 107 primary cases by sequencing 670 genes mutated in haematological malignancies. SETBP1, ASXL1 and RELN mutations were significantly associated with primary chemoresistance. We identified genomic alterations not previously described in AML, together with distinct genes that were significantly overexpressed in therapy-resistant AML. Defined gene mutations were sufficient to explain primary induction failure in only a minority of cases. Thus, additional genetic or molecular mechanisms must cause primary chemoresistance in paediatric and adult AML.

Genomic characterization of high-risk non-muscle invasive bladder cancer.

The genetic mechanisms associated with progression of high-risk non-muscle-invasive bladder cancer (HR-NMIBC) have not been described. We conducted selective next-generation sequencing (NGS) of HR-NMIBC and compared the genomic profiles of cancers that responded to intravesical therapy and those that progressed to muscle-invasive or advanced disease. DNA was extracted from paraffin-embedded sections from 25 HR-NMIBCs (22 with T1HG; 3 with TaHG with or without carcinoma in situ). Ten patients with HR-NMIBC developed progression (pT2+ or N+) ("progressors"). Fifteen patients had no progression ("non-progressors"). Tissue from 11 patients with metastatic bladder cancer (BC) were analyzed for comparison. We found no difference in frequency of mutations of TP53, PIK3CA, or KMT2D between the primary tumors of progressors compared to non-progressors and metastatic tumors. An increased frequency of deletions of CDKN2A/B was identified in tumors at progression (37%) compared to non-progressors (6%) (p = 0.10). We found a significant decrease in total mutational burden (TMB) that has been associated with immunotherapy response comparing non-progressors, progressors and metastatic tumors at 15, 10.1 and 5.1 mutations/MB respectively (p = 0.02). This association suggests more advanced tumors have decreased neoantigen burden and may explain the mechanism of BCG response in non-progressors. We found no novel genetic drivers in progressors and HR-NMIBC had many genetic features similar to metastatic BC. Loss of CDKN2A/B may occur late during invasion of BC and may represent an important step in progression. Further research is necessary to evaluate TMB and loss of CDKN2A/B locus as a biomarker for progression of NMIBC.

Targeted Next Generation Sequencing Identifies Markers of Response to PD-1 Blockade.

Therapeutic antibodies blocking programmed death-1 and its ligand (PD-1/PD-L1) induce durable responses in a substantial fraction of melanoma patients. We sought to determine whether the number and/or type of mutations identified using a next-generation sequencing (NGS) panel available in the clinic was correlated with response to anti-PD-1 in melanoma. Using archival melanoma samples from anti-PD-1/PD-L1-treated patients, we performed hybrid capture-based NGS on 236-315 genes and T-cell receptor (TCR) sequencing on initial and validation cohorts from two centers. Patients who responded to anti-PD-1/PD-L1 had higher mutational loads in an initial cohort (median, 45.6 vs. 3.9 mutations/MB; P = 0.003) and a validation cohort (37.1 vs. 12.8 mutations/MB; P = 0.002) compared with nonresponders. Response rate, progression-free survival, and overall survival were superior in the high, compared with intermediate and low, mutation load groups. Melanomas with NF1 mutations harbored high mutational loads (median, 62.7 mutations/MB) and high response rates (74%), whereas BRAF/NRAS/NF1 wild-type melanomas had a lower mutational load. In these archival samples, TCR clonality did not predict response. Mutation numbers in the 315 genes in the NGS platform strongly correlated with those detected by whole-exome sequencing in The Cancer Genome Atlas samples, but was not associated with survival. In conclusion, mutational load, as determined by an NGS platform available in the clinic, effectively stratified patients by likelihood of response. This approach may provide a clinically feasible predictor of response to anti-PD-1/PD-L1. Cancer Immunol Res; 4(11); 959-67. ©2016 AACR.

Genomic Alterations Observed in Colitis-Associated Cancers Are Distinct From Those Found in Sporadic Colorectal Cancers and Vary by Type of Inflammatory Bowel Disease.

BACKGROUND & AIMS: Patients with inflammatory bowel diseases, such as Crohn's disease (CD) and ulcerative colitis (UC), are at increased risk for small bowel or colorectal cancers (colitis-associated cancers [CACs]). We compared the spectrum of genomic alterations in CACs with those of sporadic colorectal cancers (CRCs) and investigated differences between CACs from patients with CD vs UC. METHODS: We studied tumor tissues from patients with CACs treated at Memorial Sloan Kettering Cancer Center or Weill Cornell Medical College from 2003 through 2015. We performed hybrid capture-based next-generation sequencing analysis of >300 cancer-related genes to comprehensively characterize genomic alterations. RESULTS: We performed genomic analyses of 47 CACs (from 29 patients with UC and 18 with CD; 43 primary tumors and 4 metastases). Primary tumors developed in the ileum (n = 2), right colon (n = 18), left colon (n = 6), and rectosigmoid or rectum (n = 21). We found genomic alterations in TP53, IDH1, and MYC to be significantly more frequent, and mutations in APC to be significantly less frequent, than those reported in sporadic CRCs by The Cancer Genome Atlas or Foundation Medicine. We identified genomic alterations that might be targeted by a therapeutic agent in 17 of 47 (36%) CACs. These included the mutation encoding IDH1 R132; amplification of FGFR1, FGFR2, and ERBB2; and mutations encoding BRAF V600E and an EML4-ALK fusion protein. Alterations in IDH1 and APC were significantly more common in CACs from patients with CD than UC. CONCLUSIONS: In an analysis of CACs from 47 patients, we found significant differences in the spectrum of genomic alterations in CACs compared with sporadic CRCs. We observed a high frequency of IDH1 R132 mutations in patients with CD but not UC, as well as a high frequency of MYC amplification in CACs. Many genetic alterations observed in CACs could serve as therapeutic targets.

Genomic Characterization of Renal Cell Carcinoma with Sarcomatoid Dedifferentiation Pinpoints Recurrent Genomic Alterations.

BACKGROUND: The genomic features underpinning renal cell carcinoma with sarcomatoid dedifferentiation (sRCC) are not well understood, and at present, there are no specific or effective therapies for sRCC. OBJECTIVE: To identify genomic alterations in patients with sRCC. DESIGN, SETTING, AND PARTICIPANTS: We conducted genomic profiling on paired epithelial and sarcomatoid areas of three sRCC cases. Genomic profiling was performed on another 23 sRCC patients harboring diverse epithelial components (total of 26 cases). Genomic profiling was conducted using a hybrid capture DNA next-generation sequencing assay of 236 cancer-related genes plus 19 genes frequently rearranged in cancer. Results were compared with 56 similarly sequenced cases of clear cell RCC (ccRCC) devoid of a sarcomatoid component, and with clear cell, papillary, and chromophobe renal cell carcinoma datasets from The Cancer Genome Atlas. Four additional ccRCC cases underwent whole exome sequencing. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Genomic alterations in patients with sRCC and ccRCC were described, and their frequencies were compared using the Fisher exact test. RESULTS AND LIMITATIONS: Two of three patients with sRCC who underwent genomic profiling of both their epithelial and sarcomatoid components demonstrated identical mutational profiles, and a third case demonstrated commonly disrupted genes. Of the 26 sRCCs, TP53 (42.3%), VHL (34.6%), CDKN2A (26.9%), and NF2 (19.2%) were the most frequently altered genes. NF2 mutations were mutually exclusive with TP53 but not with VHL mutations. Limitations include the small sample size. CONCLUSIONS: We found that sRCC contains different driver mutations than ccRCC. The epithelial and sarcomatoid components of sRCC largely contain the same genomic features. On the basis of harboring either TP53 or NF2 mutations, sRCC can be divided into two groups. These findings may have implications for understanding the oncogenesis of sarcomatoid renal tumors and for defining systemic treatment options. PATIENT SUMMARY: Next-generation sequencing of tumors from patients with sarcomatoid kidney cancer reveals mutations that differ from those in nonsarcomatoid patients. These findings have implications in understanding the pathobiology of sarcomatoid kidney cancer and indicate the need for a different treatment approach in these patients.

Renal carcinoma associated with a novel succinate dehydrogenase A mutation: a case report and review of literature of a rare subtype of renal carcinoma.

Renal cell carcinoma (RCC) linked to germline mutation of succinate dehydrogenase subunits A, B, C, and D (SDHA, SDHB, SDHC, and SDHD, respectively) has been recently included as a provisional entity in the 2013 International Society of Urological Pathology Vancouver classification. Most SDH-deficient tumors show SDHB mutation, with only a small number of RCC with SDHC or SDHD having been reported to date. Only one case of SDH-deficient renal carcinoma known to be SDHA mutated has been previously reported. Here we report an additional RCC harboring an SDHA mutation occurring in a 62-year-old man with right flank pain and nodal metastasis. The tumor was characterized by an infiltrative pattern with solid, acinar, and papillary components. Loss of SDHA and SDHB protein by immunohistochemistry confirmed the diagnosis. Hybrid capture-based comprehensive genomic profiling identified 3 genomic alterations in tumor tissue: (i) a novel single-nucleotide splice site deletion in SDHA gene, (ii) single-nucleotide deletion in NF2 gene, and (iii) EGFR gene amplification of 19 copies. This is the second report of SDHA-mutated RCC. With increased awareness, this rare tumor can be recognized on the basis of distinctive morphology and confirmation by immunohistochemistry and genomic profiling.

Prolonged Response to Trastuzumab in a Patient With HER2-Nonamplified Breast Cancer With Elevated HER2 Dimerization Harboring an ERBB2 S310F Mutation.

In the current genomic era, increasing evidence demonstrates that approximately 2% of HER2-negative breast cancers, by current standard testings, harbor activating mutations of ERBB2. However, whether patients with HER2-negative breast cancer with activating mutations of ERBB2 also experience response to anti-HER2 therapies remains unclear. This case report describes a patient with HER2-nonamplified heavily pretreated breast cancer who experienced prolonged response to trastuzumab in combination with pertuzumab and fulvestrant. Further molecular analysis demonstrated that her tumors had an elevated HER2 dimerization that corresponded to ERBB2 S310F mutation. Located in the extracellular domain of the HER2 protein, this mutation was reported to promote noncovalent dimerization that results in the activation of the downstream signaling pathways. This case highlights the fact that HER2-targeted therapy may be valuable in patients harboring an ERBB2 S310F mutation.

Detection of novel and potentially actionable anaplastic lymphoma kinase (ALK) rearrangement in colorectal adenocarcinoma by immunohistochemistry screening.

PURPOSE: Anaplastic lymphoma kinase (ALK) rearrangement has been detected in colorectal carcinoma (CRC) using advanced molecular diagnostics tests including exon scanning, fluorescence in situ hybridization (FISH), and next generation sequencing (NGS). We investigated if immunohistochemistry (IHC) can be used to detect ALK rearrangement in gastrointestinal malignancies. EXPERIMENTAL DESIGNS: Tissue microarrays (TMAs) from consecutive gastric carcinoma (GC) and CRC patients who underwent surgical resection at Samsung Medical Center, Seoul, Korea were screened by IHC using ALK monoclonal antibody 5A4. IHC positive cases were confirmed by FISH, nCounter assays, and NGS-based comprehensive genomic profiling (CGP). ALK IHC was further applied to CRC patients enrolled in a pathway-directed therapeutic trial. RESULTS: Four hundred thirty-two GC and 172 CRC cases were screened by IHC. No GC sample was ALK IHC positive. One CRC (0.6%) was ALK IHC positive (3+) that was confirmed by ALK FISH and a novel CAD-ALK (C35; A20) fusion variant that resulted from a paracentric inversion event inv(2)(p22-21p23) was identified by CGP. One out of 50 CRC patients enrolled in a pathway-directed therapeutic trial was ALK IHC positive (3+) confirmed by ALK FISH and found to harbor the EML4-ALK (E21, A20) fusion variant by CGP. Growth of a tumor cell line derived from this EML4-ALK CRC patient was inhibited by ALK inhibitors crizotinib and entrectinib. CONCLUSIONS: ALK IHC is a viable screening strategy for identifying ALK rearrangement in CRC. ALK rearrangement is a potential actionable driver mutation in CRC based on survival inhibition of patient tumor-derived cell line by potent ALK inhibitors.

Identification and characterization of RET fusions in advanced colorectal cancer.

There is an unmet clinical need for molecularly directed therapies available for metastatic colorectal cancer. Comprehensive genomic profiling has the potential to identify actionable genomic alterations in colorectal cancer. Through comprehensive genomic profiling we prospectively identified 6 RET fusion kinases, including two novel fusions of CCDC6-RET and NCOA4-RET, in metastatic colorectal cancer (CRC) patients. RET fusion kinases represent a novel class of oncogenic driver in CRC and occurred at a 0.2% frequency without concurrent driver mutations, including KRAS, NRAS, BRAF, PIK3CA or other fusion tyrosine kinases. Multiple RET kinase inhibitors were cytotoxic to RET fusion kinase positive cancer cells and not RET fusion kinase negative CRC cells. The presence of a RET fusion kinase may identify a subset of metastatic CRC patients with a high response rate to RET kinase inhibition. This is the first characterization of RET fusions in CRC patients and highlights the therapeutic significance of prospective comprehensive genomic profiling in advanced CRC.

Genomic alterations in DNA repair and chromatin remodeling genes in estrogen receptor-positive metastatic breast cancer patients with exceptional responses to capecitabine.

We analyzed the genomic and phosphoproteomic profiles of breast cancer tissue obtained from six patients with estrogen receptor (ER)-positive, HER2-negative metastatic breast cancer who had highly durable (≥ 5 years) and, in some cases, ongoing clinical responses with capecitabine. Formalin-fixed, paraffin-embedded tissue samples from patients' primary (n = 4) or metastatic (n = 2) breast cancers were utilized for targeted next-generation sequencing and reversed phase protein microarray. Two patients received capecitabine monotherapy. Four patients received capecitabine in combination with paclitaxel; three of these continued single-agent capecitabine after stopping paclitaxel. Capecitabine was discontinued for progressive disease after a mean of 66 months in four patients (range 54-86 months), and two patients remain on therapy, having received capecitabine for >91 months and >122 months, respectively. Three patients' cancers (50%) had likely functional alterations in DNA repair and chromatin remodeling genes, while three other patients' cancers had variants of unknown significance in these pathways. Mutations in PIK3CA, amplifications of FGFR1 or ZNF703, or phosphorylation of HER family receptors and their downstream proteins did not preclude exceptional responses to capecitabine. None of the patients' tumors harbored TP53 or PTEN mutations. Four of the patients had breast cancer tissue available for PTEN immunohistochemistry, and all four patients' cancers were positive for PTEN. These surprising findings in a group of phenotypically similar patients with ER-positive, endocrine therapy-pretreated, HER2-negative metastases, are supported by preclinical data showing that sensitivity to 5-fluorouracil is enhanced by deficiencies in chromatin remodeling and homologous recombination genes. Our findings suggest that mutations that inactivate homologous recombination and/or chromatin remodeling genes within ER-positive, HER2-negative breast cancers may predict for highly durable responses to capecitabine.

Broad, Hybrid Capture-Based Next-Generation Sequencing Identifies Actionable Genomic Alterations in Lung Adenocarcinomas Otherwise Negative for Such Alterations by Other Genomic Testing Approaches.

PURPOSE: Broad, hybrid capture-based next-generation sequencing (NGS), as a clinical test, uses less tissue to identify more clinically relevant genomic alterations compared with profiling with multiple non-NGS tests. We set out to determine the frequency of such genomic alterations via this approach in tumors in which previous extensive non-NGS testing had not yielded a targetable driver alteration. EXPERIMENTAL DESIGN: We enrolled patients with lung adenocarcinoma with a ≤ 15 pack-year smoking history whose tumors previously tested "negative" for alterations in 11 genes (mutations in EGFR, ERBB2, KRAS, NRAS, BRAF, MAP2K1, PIK3CA, and AKT1 and fusions involving ALK, ROS1, and RET) via multiple non-NGS methods. We performed hybridization capture of the coding exons of 287 cancer-related genes and 47 introns of 19 frequently rearranged genes and sequenced these to deep, uniform coverage. RESULTS: Actionable genomic alterations with a targeted agent based on NCCN guidelines were identified in 26% [8 of 31: EGFR G719A, BRAF V600E, SOCS5-ALK, HIP1-ALK, CD74-ROS1, KIF5B-RET (n = 2), CCDC6-RET]. Seven of these patients either received or are candidates for targeted therapy. Comprehensive genomic profiling using this method also identified a genomic alteration with a targeted agent available on a clinical trial in an additional 39% (12 of 31). CONCLUSIONS: Broad, hybrid capture-based NGS identified actionable genomic alterations in 65% [95% confidence interval (CI), 48%-82%] of tumors from never or light smokers with lung cancers deemed without targetable genomic alterations by earlier extensive non-NGS testing. These findings support first-line profiling of lung adenocarcinomas using this approach as a more comprehensive and efficient strategy compared with non-NGS testing. See related commentary by McCutcheon and Giaccone, p. 3584.

Comprehensive genomic profiling of pancreatic acinar cell carcinomas identifies recurrent RAF fusions and frequent inactivation of DNA repair genes.

UNLABELLED: Pancreatic acinar cell carcinomas (PACC) account for approximately 1% (∼500 cases) of pancreatic cancer diagnoses annually in the United States. Oncogenic therapuetic targets have proven elusive in this disease, and chemotherapy and radiotherapy have demonstrated limited efficacy against these tumors. Comprehensive genomic profiling of a large series of PACCs (n=44) identified recurrent rearrangements involving BRAF and RAF1 (CRAF) in approximately 23% of tumors. The most prevalent fusion, SND1-BRAF, resulted in activation of the MAPK pathway, which was abrogated with MEK inhibition. SND1-BRAF-transformed cells were sensitive to treatment with the MEK inhibitor trametinib. PACCs lacking RAF rearrangements were significantly enriched for genomic alterations, causing inactivation of DNA repair genes (45%); these genomic alterations have been associated with sensitivity to platinum-based therapies and PARP inhibitors. Collectively, these results identify potentially actionable genomic alterations in the majority of PACCs and provide a rationale for using personalized therapies in this disease. SIGNIFICANCE: PACC is genomically distinct from other pancreatic cancers. Fusions in RAF genes and mutually exclusive inactivation of DNA repair genes represent novel potential therapeutic targets that are altered in over two thirds of these tumors.

Comprehensive genomic profiling of relapsed and metastatic adenoid cystic carcinomas by next-generation sequencing reveals potential new routes to targeted therapies.

We hypothesized that next-generation sequencing could reveal actionable genomic alterations (GAs) and potentially expand treatment options for patients with advanced adenoid cystic carcinoma (ACC). Genomic profiling using next-generation sequencing was performed on hybridization-captured, adapter ligation libraries derived from 28 relapsed and metastatic formalin-fixed paraffin-embedded ACC. The 3230 exons of 182 cancer-related genes and 37 introns of 14 genes frequently rearranged in cancer were fully sequenced using the Illumina HiSeq 2000. All classes of GAs were evaluated. Actionable GAs were defined as those impacting targeted anticancer therapies on the market or in registered clinical trials. A total of 44 GAs were identified in the 28 ACC tumors, with 12 of 28 (42.9%) of tumors harboring at least 1 potentially actionable GA. The most common nonactionable GAs were identified in KD6MA (5 cases; 18%), ARID1A (4 cases; 14%), RUNX1 (2 cases; 7%), and MYC (2 cases; 7%). Actionable GAs included NOTCH1 (3 cases; 11%), MDM2 (2 cases; 7%), PDGFRA (2 cases; 7%), and CDKN2A/B (p16) (2 cases; 7%). Other potentially actionable GAs identified in a single case included: mutations in AKT1, BAP1, EGFR, and PIK3CA, homozygous deletion of FBXW7, and amplifications of CDK4, FGFR1, IGF1R, KDR, KIT, and MCL1. The frequency of GA in ACC is lower than that seen in the more common solid tumors. Comprehensive genomic profiling of ACC can identify actionable GAs in a subset of patients that could influence therapy for these difficult-to-treat progressive neoplasms.

Advanced urothelial carcinoma: next-generation sequencing reveals diverse genomic alterations and targets of therapy.

Although urothelial carcinoma (UC) of the urinary bladder generally portends a favorable prognosis, metastatic tumors often follow an aggressive clinical course. DNA was extracted from 40 µm of formalin-fixed, paraffin-embedded (FFPE) sections from 35 stage IV UCs that had relapsed and progressed after primary surgery and conventional chemotherapy. Next-generation sequencing (NGS) was performed on hybridization-captured, adaptor ligation-based libraries for 3320 exons of 182 cancer-related genes plus 37 introns from 14 genes frequently rearranged in cancer to at an average sequencing depth of 1164 × and evaluated for all classes of genomic alterations (GAs). Actionable GAs were defined as those impacting the selection of targeted anticancer therapies on the market or in registered clinical trials. A total of 139 GAs were identified, with an average of 4.0 GAs per tumor (range 0-10), of which 78 (56%) were considered actionable, with an average of 2.2 per tumor (range 0-7). Twenty-nine (83%) cases harbored at least one actionable GA including: PIK3CA (9 cases; 26%); CDKN2A/B (8 cases; 23%); CCND1 (5 cases; 14%); FGFR1 (5 cases; 14%); CCND3 (4 cases; 11%); FGFR3 (4 cases; 11%); MCL1 (4 cases; 11%); MDM2 (4 cases; 11%); EGFR (2 cases, 6%); ERBB2 (HER2/neu) (2 cases, 6%); NF1 (2 cases, 6%) and TSC1 (2 cases, 6%). Notable additional alterations included TP53 (19 cases, 54%) and RB1 (6 cases; 17%). Genes involved in chromatin modification were altered by nonsense mutation, splice site mutation or frameshift indel in a mutually exclusive manner in nearly half of all cases including KDM6A (10 cases; 29%) and ARID1A (7 cases; 20%). Comprehensive NGS of 35 UCs of the bladder revealed a diverse spectrum of actionable GAs in 83% of cases, which has the potential to inform treatment decisions for patients with relapsed and metastatic disease.

Development and validation of a clinical cancer genomic profiling test based on massively parallel DNA sequencing.

As more clinically relevant cancer genes are identified, comprehensive diagnostic approaches are needed to match patients to therapies, raising the challenge of optimization and analytical validation of assays that interrogate millions of bases of cancer genomes altered by multiple mechanisms. Here we describe a test based on massively parallel DNA sequencing to characterize base substitutions, short insertions and deletions (indels), copy number alterations and selected fusions across 287 cancer-related genes from routine formalin-fixed and paraffin-embedded (FFPE) clinical specimens. We implemented a practical validation strategy with reference samples of pooled cell lines that model key determinants of accuracy, including mutant allele frequency, indel length and amplitude of copy change. Test sensitivity achieved was 95-99% across alteration types, with high specificity (positive predictive value >99%). We confirmed accuracy using 249 FFPE cancer specimens characterized by established assays. Application of the test to 2,221 clinical cases revealed clinically actionable alterations in 76% of tumors, three times the number of actionable alterations detected by current diagnostic tests.

Identification of new ALK and RET gene fusions from colorectal and lung cancer biopsies.

Applying a next-generation sequencing assay targeting 145 cancer-relevant genes in 40 colorectal cancer and 24 non-small cell lung cancer formalin-fixed paraffin-embedded tissue specimens identified at least one clinically relevant genomic alteration in 59% of the samples and revealed two gene fusions, C2orf44-ALK in a colorectal cancer sample and KIF5B-RET in a lung adenocarcinoma. Further screening of 561 lung adenocarcinomas identified 11 additional tumors with KIF5B-RET gene fusions (2.0%; 95% CI 0.8-3.1%). Cells expressing oncogenic KIF5B-RET are sensitive to multi-kinase inhibitors that inhibit RET.