Impact of age on genomic alterations associated with pancreatic ductal adenocarcinoma (PDAC).

2017 ◽  
Vol 35 (4_suppl) ◽  
pp. 282-282
Author(s):  
Ben George ◽  
Mark Bailey ◽  
Alexa Betzig Schrock ◽  
Lauren Thorpe ◽  
Laurie M. Gay ◽  
...  
Keyword(s):  
Large Scale ◽  
Kinase Domain ◽  
Ductal Adenocarcinoma ◽  
Genomic Alterations ◽  
Kras Mutations ◽  
Entire Study ◽  
Formalin Fixed Paraffin Embedded ◽  
Comprehensive Genomic Profiling ◽  
Tumor Mutational Burden ◽  
Metastatic Sites

282 Background: Large scale, retrospective, sequencing projects have identified well-defined subtypes of PDAC, but therapeutic paradigms remain unchanged. We hypothesized that genomic alterations associated with PDAC in young adults (YA, age < 50) are distinctly different from that of older adults (OA, age > 50) to identify an enrichment of targetable alterations. Methods: DNA was extracted from formalin fixed paraffin embedded (FFPE) PDAC clinical specimens and comprehensive genomic profiling (CGP) was performed on hybrid-capture, adaptor ligation based libraries to a mean coverage depth of > 600 for up to 315 genes plus 47 introns from 19 genes frequently rearranged in cancer. Results: CGP was performed on 1533 FFPE PDAC specimens, 566 (36.9%) were from the primary tumor, 967 (63.1%) from metastatic sites. Median age at diagnosis was 63 years (yrs), 180 (11.7%) were YA. KRAS mutations were identified in 78.7 of YA and 87.7% of OA. The differentially altered genes between the two groups were KRAS (p = 0.004), TP53 (p = 0.04), BRCA2 (p = 0.02), AKT2 (p = 0.03), MAP2K4 (P = 0.003) and DNMT3A (p = 0.0002). The median tumor mutational burden (TMB) for the entire study set was 2.7 (YA – 2.5, OA –2.7). BRAF kinase domain deletion was observed in 1 patient (OA). ALK fusions were present in 2 patients (1 YA & 1 OA) and these patients had durable responses to specific ALK inhibitors. Conclusions: The majority of the genomic alterations identified were not significantly different on the basis of age. However, identification of subpopulations, such as ALK kinase fusions and BRAF kinase domain deletions that can translate into sustained clinical benefit from matched targeted therapy is promising. This underscores the importance of CGP in PDAC to investigate other targetable genomic alterations.

Comprehensive genomic profiling (CGP) in KRAS wild-type (WT) pancreatic ductal adenocarcinoma (PDAC).

2018 ◽  
Vol 36 (4_suppl) ◽  
pp. 271-271
Author(s):  
Ben George ◽  
Joel R. Greenbowe ◽  
Andrew Eugene Hendifar ◽  
Talia Golan ◽  
Milind M. Javle ◽  
...  
Keyword(s):  
Predictive Biomarkers ◽  
Parp Inhibitors ◽  
Chemotherapeutic Agents ◽  
Ductal Adenocarcinoma ◽  
Genomic Alteration ◽  
Damage Repair ◽  
Formalin Fixed Paraffin ◽  
Formalin Fixed Paraffin Embedded ◽  
Comprehensive Genomic Profiling ◽  
Tumor Mutational Burden

271 Background: Mutations in oncogenic KRAS have been widely accepted as the signature genomic alteration (GA) in sporadic PDAC, but therapeutic efforts aimed at targeting constitutively activated KRAS have been disappointing. We examined somatic GAs in KRAS WT PDAC utilizing a CGP platform to identify actionable targets. Methods: DNA was extracted from formalin fixed paraffin embedded (FFPE) PDAC clinical specimens and CGP was performed on hybrid-capture, adaptor ligation based libraries to a mean coverage depth of > 600 unique reads. Alterations in the RAS/ RAF/ MEK pathway genes ( KRAS, NRAS, HRAS, ARF, BRAF, EGFR, MAP2K2, MAP2K1, MAPK1) and DNA Damage Repair (DDR) pathway genes ( BRCA1/2, ATM, ATR, BRIP1, RAD50, RAD51, RAD52, PALB2, CHEK1, CHEK2) were examined. Tumor mutational burden (TMB) was determined on 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. TMB was categorized based on mutations(m)/Mbp of DNA - high (H; > 20), Intermediate (I; 8-20) and low (L; < 8). Results: CGP was performed on 3426 PDAC specimens; 1815 (53%) were male, 390 (11.3%) were KRAS WT. GAs in the RAS/ RAF/ MEK pathway were identified in 90.6% of all cases, while 68 (17.4%) KRAS WT cases had one or more GAs in RAS/ RAF/ MEK pathway genes. DDR pathway GAs were identified in 1405 (41%) cases for a total of 2050 GAs, and 180 (46%) KRAS WT cases for a total of 285 GAs. DDR pathway alterations were common in KRAS WT PDAC compared to KRAS mutated PDAC (p = 0.028). Among the 842 (24.6%) cases with available TMB data, 5 (0.6%), 104 (12.3%) and 733 (87.1%) pts had H, I and L, TMB respectively. Among 88 (22.6%) KRAS WT cases with available TMB data, 2 (2.3%), 12 (13.6%) and 74 (84.1%) pts had H, I and L, TMB, respectively. MSI status was available in 2314 (67.5%) cases, 13 (0.6%) were MSI-high (MSI-H); among the KRAS WT cases, 222 (57%) had MSI status available, 3 (1.3%) were MSI-H. Conclusions: MSI-H status and high TMB are rare in PDAC, regardless of KRAS mutation status. GAs in the DDR pathway are relatively common in PDAC and may serve as predictive biomarkers for platinum chemotherapeutic agents and/or PARP inhibitors. Prospective validation of such predictive gene signatures will improve therapeutic efficacy and minimize toxicities.

Comprehensive genomic profiling of neuroendocrine carcinoma of the prostate.

2016 ◽  
Vol 34 (2_suppl) ◽  
pp. 187-187
Author(s):  
Sumanta K. Pal ◽  
Matthew I. Milowsky ◽  
Julia Andrea Elvin ◽  
Siraj Mahamed Ali ◽  
Jean H. Hoffman-Censits ◽  
...  
Keyword(s):  
Neuroendocrine Carcinoma ◽  
Stage Iv ◽  
Mtor Inhibitors ◽  
Mtor Pathway ◽  
Tumor Type ◽  
Genomic Profiling ◽  
Genomic Alterations ◽  
Carcinoma Of The Prostate ◽  
Comprehensive Genomic Profiling ◽  
Metastatic Sites

187 Background: Neuroendocrine carcinoma of the prostate (NCAP) is an aggressive high grade malignancy that often presents as metastatic disease. Current treatments of this tumor have only modest benefit leading investigators to query whether comprehensive genomic profiling (CGP) would have potential to discover novel targets of therapy. Methods: DNA was extracted from 40 microns of FFPE sections from 37 consecutive cases of relapsed/metastatic NCAP. CGP was performed on hybridization-captured, adaptor ligation based libraries to a mean coverage depth of 583X for up to 315 cancer-related genes plus 37 introns from 14 genes frequently rearranged in cancer. Genomic alterations (GA) included base substitutions (SUB), INDELs, copy number alterations (CNA) and fusions/rearrangements. Clinically relevant GA (CRGA) were defined as GA linked to drugs on the market or under evaluation in mechanism driven clinical trials. Results: The median age of the men in this study was 65.1 years (range 43 to 83 years). All (100%) cases were positive for neuroendocrine markers on immunohistochemical staining and were Stage IV at the time of CGP. Samples used for sequencing were obtained from the primary tumor in 9 (24%) of NCAP and from metastatic sites in 28 (76%) of NCAP (12 liver, 6 LN, 2 each from bladder, pelvis and soft tissue, and 1 each from rectum, bone, urethra and ureter. There were 213 total GA (5.8 GA/sample) and 47 CRGA (1.3 CRGA/sample). The most frequent GA were non-CRGA mutations in TP53 (68%) and RB1 (51%). TMPRSS:ERG fusions were identified in 32% of cases whereas AR was altered in 8% (1 mutation and 2 amplifications). The most frequent CRGA involved PTEN (32%), BRCA2 (14%), FGFR1 (5%), PIK3CA (5%) and AKT2 (3%). No alterations in BRAF were identified. Clinical responses to MTOR inhibitors in patients with MTOR pathway alterations will be presented. Conclusions: NCAP has distinctive genomic alterations from classic acinar CAP including reduced frequencies of alterations in TMPRSS:ERG and AR and frequent RB1 mutations. Multiple alterations in the MTOR pathway identified in this infrequent tumor type suggest that these patients may be candidates for MTOR inhibitors and other targeted therapies.

KRAS amplification and mutation as independent events in gastroesophageal adenocarcinomas (GEA).

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e15565-e15565
Author(s):  
Joseph Chao ◽  
Russell Madison ◽  
Jeffrey S. Ross ◽  
Vincent A. Miller ◽  
Siraj Mahamed Ali ◽  
...  
Keyword(s):  
Kras Mutation ◽  
Checkpoint Inhibitors ◽  
Treatment Strategies ◽  
Older Patient ◽  
Kras Mutations ◽  
Independent Events ◽  
Comprehensive Genomic Profiling ◽  
Tumor Mutational Burden ◽  
Tissue Specimens ◽  
Kras Codon

e15565 Background: KRAS mutations are common oncogenic events across cancers, but effective RAS-directed therapies are lacking. However, recent studies support use of PD-1 blockade in most subsets of lung cancer with KRAS short variant mutations (KRASSV) (PMID: 28039262), and preclinical data supports combined MEK and SHP2 inhibition in KRAS amplified ( KRASa) GEA (PMID: 30093730). We sought to explore the landscape of KRAS altered GEA and compare genomic profiles of KRAS-altered and KRAS wild-type (WT) cases for biomarkers of response to targeted therapies and immune checkpoint inhibitors. Methods: 6,667 tissue specimens from patients with advanced GEA were assayed using hybrid capture-based comprehensive genomic profiling. Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 95 or 114 loci. Descriptive statistics were used to compare among subgroups. Results: KRASSV and KRASa were identified in 11% and 5.8% of gastric adenocarcinoma (GA), respectively, and in 7.2% and 17% of esophageal adenocarcinoma (EA), respectively. KRASa and KRASSV were nearly mutually exclusive, co-occurring in only 4.4% of KRAS altered cases. ERBB2 alterations were less common in KRASSV and KRASa GEA (both 9%) as compared with KRAS WT GEA (19%) (p = 1.9E-16). EGFRa was less common in KRASSV vs KRASa GEA (1.9% vs 9.3%, p = 2.6E-8), whereas PIK3CASV was more common in KRASSV vs KRASa (16% vs 5.0%, p = 1.5E-11). Median TMB for all groups was similar; however, KRASSV GEA had a higher mean TMB (9.7 mut/Mb) as compared to KRASa (5.1 mut/Mb, p = 5.0E-12) and KRAS WT cases (5.8 mut/Mb, p = 2.2E-07). KRAS codon 12/13 accounted for > 80% of predicted pathogenic mutations. MSI-high was also more prevalent in KRASSV (11.3%) vs KRASa (0.9%, p = 4.8E-15) and KRAS WT GEA (2.4%, p = 1.8E-25). MSI-high KRASSV GEA was associated with older patient age (median 72 years) and with high TMB (median 40.9 mut/mb). Conclusions: GA was enriched for KRAS mutation whereas EA was enriched for KRAS amplification. KRAS WT vs KRASSV vs KRASa each presented distinct genomic profiles. KRASa in the absence of KRAS mutation exists in 11% of GEA and warrants further exploration to inform combination treatment strategies.

PD-L1 expression, tumor mutational burden, and microsatellite instability status in 746 pancreas ductal adenocarcinomas.

2020 ◽  
Vol 38 (4_suppl) ◽  
pp. 757-757
Author(s):  
Amanda Hemmerich ◽  
Claire I. Edgerly ◽  
Daniel Duncan ◽  
Richard Huang ◽  
Natalie Danziger ◽  
...  
Keyword(s):  
Microsatellite Instability ◽  
Mutational Burden ◽  
Formalin Fixed Paraffin ◽  
Formalin Fixed Paraffin Embedded ◽  
Comprehensive Genomic Profiling ◽  
Tumor Mutational Burden ◽  
Positive Score ◽  
Combined Positive Score ◽  
High Level ◽  
Positive Groups

757 Background: Pancreas ductal adenocarcinomas (PDA) has a 5-year survival rate of 6% with a need for new therapeutic options. The approval of pembrolizumab for some gastrointestinal cancers shows the potential of immunotherapy (IMT) in PDA. We evaluated the IMT-associated biomarkers of PD-L1 expression, tumor mutational burden (TMB), microsatellite instability (MSI) and PD-L1 amplification in PDAs. Methods: 746 formalin-fixed paraffin embedded samples were evaluated for PD-L1 IHC using the Dako 22C3 pharmDx assay and scored using tumor proportion score (TPS). The cases had comprehensive genomic profiling (CGP) via DNA sequencing, using a hybrid-capture next-generation sequencing assay (FoundationOne and FoundationOneCDx) for genomic alterations (GAs), TMB, and MSI. Results: PD-L1 was positive (TPS ≥ 1%) in 29% (214/746) and negative in 71% (532/746). 43/214 (20%) of positive cases were high positive (TPS ≥ 50%). TMB (590 cases) had a mean of 3.20, 3.46, and 3.61 mutations/Mb for PD-L1 negative, positive, and high positive groups. 3 hypermutated (TMB ≥ 20) were negative for PD-L1 expression. 3/581 cases were MSI-high with a high TMB score (average 23.53 mutations/Mb). 2 MSI-high cases were negative for PD-L1 and 1 was high positive. PD-L1 amplification was not detected (0/746). Only BCOR was significantly different between PD-L1 high positive and PD-L1 negative tumors (Table). Conclusions: Of 729 PDA cases, 29% were positive (TPS ≥ 1%) for PD-L1 expression while only 6% of all cases showed a high level of PD-L1 expression on tumor cells. TMB high (3/729) and MSI-High (3/729) cases were rare. Only 2 of the TMB high cases were also MSI-high. PD-L1 amplification was not detected. Comparing GAs in PD-L1 high positive vs negative cases was only significantly different for BCOR. Further investigation is needed to see if a combined positive score of PD-L1 expression may identify a subset of patients with PDA who are more likely to respond to IMT. [Table: see text]

NF2 mutation-driven renal cell carcinomas (RCC): A comprehensive genomic profiling (CGP) study.

2020 ◽  
Vol 38 (6_suppl) ◽  
pp. 726-726
Author(s):  
Evgeny Yakirevich ◽  
Carmen Perrino ◽  
Andrea Necchi ◽  
Petros Grivas ◽  
Gennady Bratslavsky ◽  
...  
Keyword(s):  
Clear Cell ◽  
Collecting Duct ◽  
High Status ◽  
Genomic Alterations ◽  
Mutational Burden ◽  
Gender And Age ◽  
Comprehensive Genomic Profiling ◽  
Tumor Mutational Burden ◽  
Male Preponderance ◽  
Ffpe Tissues

726 Background: NF2 genomic alterations (GA) have been associated with aggressive behavior in RCC. Methods: FFPE tissues from 1,386 clear cell (ccRCC), 307 papillary (pRCC), 72 chromophobe (chRCC), 145 sarcomatoid (sRCC), 54 collecting duct (cdRCC),37 medullary (medRCC) and 134 unclassified (nosRCC) underwent hybrid-capture based CGP to evaluate all classes of genomic alterations (GA). Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and MSI was determined on 114 loci. PD-L1 expression was determined by IHC (Dako 22C3). Results: 140 (7%) RCC featured NF2 GA which were predominantly short variant (SV) mutations. Gender and age were similar with male preponderance in all histologic subtypes. NF2 GA frequency was highest in cdRCC (20%) and sRCC (19%) and lowest in ccRCC (3%). The medRCC at 5% NF2 GA and chRCC at 0% NF2 GA were not further evaluated. VHL and PBRM1 GA were significantly more frequent in NF2 altered ccRCC than all other RCC (P < 0.001). Other mTOR pathway GA were uncommon. Potentially targetable kinase GA in NF2-mutated RCC included BRAF (2% of ccRCC), EGFR (3% of pRCC), ERBB3 (4% of sRCC) and PIK3CA (9% of cdRCC). No NF2 mutated RCC featured MSI -high status and both TMB and PD-L1 expression levels were extremely low in all subsets with exception of high PD-L1 staining in sRCC tumors. Conclusions: cdRCC, sRCC, pRCC and nosRCC are enriched in NF2 GA. Low PBRM1 GA, TMB and MSI- high predict resistance to immunotherapy in NF2 mutated RCC although the high PD-L1 expression in sRCC is noteworthy.[Table: see text]

Comprehensive genomic sequencing of prostate sarcomatoid carcinoma tumors identifies differences in genomic alterations compared to prostate adenocarcinoma tumors.

2017 ◽  
Vol 35 (6_suppl) ◽  
pp. 226-226 ◽  
Author(s):  
Sherri Z. Millis ◽  
Philip J. Stephens ◽  
Jeffrey S. Ross ◽  
Vincent A. Miller ◽  
Siraj Mahamed Ali ◽  
...  
Keyword(s):  
Clinical Care ◽  
Treatment Options ◽  
Sarcomatoid Carcinoma ◽  
Prostate Adenocarcinoma ◽  
Copy Number Alterations ◽  
Genomic Alterations ◽  
Comprehensive Genomic Profiling ◽  
Tumor Mutational Burden ◽  
Prostate Cancers ◽  
Worse Prognosis

226 Background: Sarcomatoid carcinoma of the prostate is a rare variant of prostatic cancer and has a significantly worse prognosis. The genomic features underpinning this rare subtype of malignancy are not well understood, and at present, there are no effective therapies. Methods: Tissue from 1417 prostate cancer patients was assayed by hybrid-capture based comprehensive genomic profiling (CGP) in the course of clinical care to evaluate genomic alterations (GA: base substitutions, indels, amplifications, copy number alterations, fusions/rearrangements) and targeted therapy opportunities. Tumor mutational burden (TMB) was calculated from a minimum of 1.11 Mb sequenced DNA and reported as mutations/Mb. Results: Profiling identified different patterns in GAs between prostate adenocarcinoma (1409) and prostate sarcomatoid carcinoma (8) (table), most notably in the commonly identified alterations in prostate cancers: TP53, RB1, and TMPRSS2-ERG. Additionally, the PI3K/mTOR pathway was altered in 50% of the sarcomatoid carcinoma cohort. None of the sarcomatoid carcinoma patients had a high TMB, while 4% of the prostate adenocarcinomas had TMB greater than 19 mutations/Mb. The sarcomatoid carcinoma cohort also had on average 8 GAs, while the prostate adenocarcinoma cohort had an average of 13 GAs. Conclusions: Genomic profiles of tumors from patients with prostate cancers reveal that those with sarcomatoid carcinoma features are more likely to have genomic alterations in TP53, RB1, and TMPRSS2 but fewer overall GA’s. Based on rearrangements and the sarcoma profile, utilization of a broad CGP panel that includes analysis of a larger panel of rearrangements identifies more commonly rearranged genes that would not be identified in non-comprehensive panels that do not evaluate these rearrangements. These findings may contribute to a better understanding of the oncogenesis of sarcomatoid prostate carcinoma and for defining novel systemic treatment options. [Table: see text]

Anal melanoma: A comparative comprehensive genomic profiling study.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 9566-9566
Author(s):  
Jeffrey S. Ross ◽  
Russell Madison ◽  
Julia Andrea Elvin ◽  
Jo-Anne Vergilio ◽  
Jonathan Keith Killian ◽  
...  
Keyword(s):  
Uv Light ◽  
Light Exposure ◽  
Mtor Pathway ◽  
Braf V600e ◽  
Genomic Profiling ◽  
Genomic Alterations ◽  
Comprehensive Genomic Profiling ◽  
Tumor Mutational Burden ◽  
Ffpe Tissues ◽  
Tumor Types

9566 Background: We performed a comprehensive genomic profiling (CGP) study of AM and CM to learn of potential genomic alterations (GA) linked to targeted and immune checkpoint inhibitor (ICPI) therapies. Methods: 90 AM and 1804 CM FFPE tissues from late stage underwent hybrid-capture based CGP to evaluate all classes of genomic alterations (GA). Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. PD-L1 expression was determined by IHC. Results: AM and CM had a similar age, but AM females and CM males were significantly more common (P < 0.0001). GA/tumor was significantly higher in CM (UV light exposure) as were the median TMB and frequency of TMB ≥ 10 and 20 mutations/Mb (P < 0.0001 for all comparisons). PD-L1 expression was higher in AM than CM (P = 0.0023). AM and CM were all MS-stable. The contrast in S FB1 mutations in AM and TERT GA in CM were significant (P < 0.0001). Of potentially targetable GA, AM featured significantly more KIT GA than CM (P < 0.0001), whereas CM featured significantly more BRAF GA (P < 0.0001). Only 11% of AM BRAF GA were V600E whereas 74% of CM BRAF GA were V600E (P < 0.0001). MTOR pathway GA were common in both tumor types. Additional potentially targetable alterations in PDGFRA and ERBB2 kinases were seen in AM but not in CM. Conclusions: CM is distinct from AM featuring higher GA/tumor, higher TMB and frequent BRAF V600E GA that predict benefit from ICPI and anti-BRAF therapies. Although both AM and CM feature MTOR pathway targets, AM does have higher PD-L1 expression than CM and is characterized by an array of potentially targetable kinase genes including KIT, PDGFRA, ERBB2 and to a lesser extent than CM, BRAF.[Table: see text]

Genomic findings in adenocarcinoma of the urinary bladder.

2019 ◽  
Vol 37 (7_suppl) ◽  
pp. 132-132
Author(s):  
Oleg Shapiro ◽  
Leszek Kotula ◽  
Timothy Byler ◽  
Joseph Jacob ◽  
Brian Michael Alexander ◽  
...  
Keyword(s):  
Ductal Carcinoma ◽  
Mtor Inhibitors ◽  
Parp Inhibitors ◽  
High Status ◽  
Genomic Alterations ◽  
Mek Inhibitors ◽  
Pathologic Features ◽  
Ffpe Samples ◽  
Comprehensive Genomic Profiling ◽  
Tumor Mutational Burden

132 Background: Prostatic ductal carcinoma (PDC) is an uncommon centrally located prostate with a characteristic tubulopapillary histology. PDC shares some biomarker features with the more common prostatic acinar carcinoma (PAC) including PSA expression. Methods: In this comparative comprehensive genomic profiling (CGP) study, FFPE samples from 61 clinically advanced PDC and 4,132 PAC were profiled for all classes of genomic alterations (GA). Tumor mutational burden (TMB) was determined on 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. Results: The age, frequency of genomic alterations (GA) per tumor and TP53 GA of PDA and PAC were similar (Table). TMPRSS2:ERG fusions and AR GA were more often identified in PAC than PDC whereas PTEN GA were more common in PDC than PAC. Targetable GA were identified at similar frequencies in both groups focused on BRCA2 (PARP inhibitors), BRAF (BRAF/MEK inhibitors) and PIK3CA (MTOR inhibitors). ATM GA (PARP inhibitors) were more common in PAC than PDC. CDK12 GA potentially associated with immunotherapy (IO) benefit were similar in PDA and PAC as were the frequencies of MSI-High status, median TMB and high TMB levels. Conclusions: The pathologic features of PDC and PAC have been classically maintained as representative of 2 different tumor types with potentially contrasting histogenesis. In the current CGP-based study, PDA and PAC did not display significant differences in genomic signatures. CGP may reveal biomarkers that could direct patients to targeted (PARP, MTOR and BRAF/MEK inhibitors) or immunotherapies ( CDK12 GA, MSI-High or high TMB status) in both PDA and PAC. [Table: see text]

KRAS amplification and mutation are independent events in gastroesophageal adenocarcinomas (GEA).

2019 ◽  
Vol 37 (4_suppl) ◽  
pp. 70-70
Author(s):  
Russell Madison ◽  
Joseph Chao ◽  
Jeffrey S. Ross ◽  
Vincent A. Miller ◽  
Siraj Mahamed Ali ◽  
...  
Keyword(s):  
Kras Mutation ◽  
Checkpoint Inhibitors ◽  
Treatment Strategies ◽  
Older Patient ◽  
Kras Mutations ◽  
Independent Events ◽  
Comprehensive Genomic Profiling ◽  
Tumor Mutational Burden ◽  
Tissue Specimens ◽  
Kras Codon

70 Background: KRAS mutations are common oncogenic events across cancers, but effective RAS-directed therapies are lacking. However, recent studies support use of PD-1 blockade in most subsets of lung cancer with KRAS short variant mutations (KRASSV) (PMID: 28039262), and preclinical data supports combined MEK and SHP2 inhibition in KRAS amplified ( KRASa) GEA (PMID: 30093730). We sought to explore the landscape of KRAS altered GEA and compare genomic profiles of KRAS-altered and KRAS wild-type (WT) cases for biomarkers of response to targeted therapies and immune checkpoint inhibitors. Methods: 6,667 tissue specimens from patients with advanced GEA were assayed using hybrid capture-based comprehensive genomic profiling. Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 95 or 114 loci. Descriptive statistics were used to compare among subgroups. Results: KRASSV and KRASa were identified in 11% and 5.8% of gastric adenocarcinoma (GA), respectively, and in 7.2% and 17% of esophageal adenocarcinoma (EA), respectively. KRASa and KRASSV were nearly mutually exclusive, co-occurring in only 4.4% of KRAS altered cases. ERBB2 alterations were less common in KRASSV and KRASa GEA (both 9%) as compared with KRAS WT GEA (19%) (p = 1.9E-16). EGFRa was less common in KRASSV versus KRASa GEA (1.9% vs. 9.3%, p = 2.6E-8), whereas PIK3CASV was more common in KRASSV versus KRASa (16% vs 5.0%, p = 1.5E-11). Median TMB for all groups was similar; however, KRASSV GEA had a higher mean TMB (9.7 mut/Mb) as compared to KRASa (5.1 mut/Mb, p = 5.0E-12) and KRAS WT cases (5.8 mut/Mb, p = 2.2E-07). KRAS codon 12/13 accounted for > 80% of predicted pathogenic mutations. MSI-high was also more prevalent in KRASSV (11.4%) versus KRASa (0.9%, p = 4.8E-15) and KRAS WT GEA (3.0%, p = 1.8E-25). MSI-high KRASSV GEA was associated with older patient age (median 72 years) and with high TMB (median 40.9 mut/mb). Conclusions: GA was enriched for KRAS mutation whereas EA was enriched for KRAS amplification. KRAS WT versus KRASSV versus KRASa each presented distinct genomic profiles. KRASa in the absence of KRAS mutation exists in 11% of GEA and warrants further exploration to inform combination treatment strategies.

Comprehensive genomic profiling (CGP) in post-systemic treatment (Post) metastatic sites (MET) and pretreatment (Pre) primary tumors (PT) of metastatic prostate cancer (mPC).

2020 ◽  
Vol 38 (6_suppl) ◽  
pp. 175-175
Author(s):  
Andrea Necchi ◽  
Petros Grivas ◽  
Gennady Bratslavsky ◽  
Oleg Shapiro ◽  
Joseph Jacob ◽  
...  
Keyword(s):  
Systemic Treatment ◽  
High Status ◽  
Liquid Biopsies ◽  
Primary Tumors ◽  
Virtual Absence ◽  
Mutational Burden ◽  
Comprehensive Genomic Profiling ◽  
Tumor Mutational Burden ◽  
Metastatic Sites ◽  
Systemic Therapies

175 Background: CGP was performed on Pre PT and Post MET including bone (BO), liver (LIV), lung (LU), brain (BN), lymph node (LN) and soft tissue (ST) mPC. Methods: 1,294 mPC underwent hybrid-capture based CGP. Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. PD-L1 expression was determined by IHC (Dako 22C3). Results: GA in AR were lowest in the Pre PT (2%) and highest in Post LU (24%) and LIV (50%). GA/tumor was significantly higher in BN (8.0) compared to PT (3.8). BR MET also featured higher PTEN GA than PT. BRCA2 GA varied from 0% in BR to 7-9% in PT, BO, LU, LN and ST to a high of 15% in LI MET. ATM GA were significantly higher in LU MET and RAD21 GA highest in LN MET. Potential predictors of IO drug response included high CDK12 GA in LU MET, MSI high status at 29% in BR MET associated with higher TMB levels, but virtual absence of high PD-L1 expression. ERBB2 GA appeared to be increased in the MET group compared with PT but BRAF GA were not. RB1 GA were significantly increased in LIV MET cases. Conclusions: CGP of mPC PT and MET demonstrates significant differences likely linked to exposure to systemic therapies. These findings suggest that, in the future, liquid biopsies may have advantages over individual MET site biopsies in their ability to capture the entire range of therapeutic opportunities for patients with advanced mPC.[Table: see text]

Sign in / Sign up

Export Citation Format

Share Document