ABSTRACT
BACKGROUND: Poly(adenosine diphosphate-ribose) polymerase inhibitors target cancers with defects in homologous recombination repair by synthetic lethality. New therapies are needed to reduce recurrence in patients with BRCA1 or BRCA2 germline mutation-associated early breast cancer. METHODS: We conducted a phase 3, double-blind, randomized trial involving patients with human epidermal growth factor receptor 2 (HER2)-negative early breast cancer with BRCA1 or BRCA2 germline pathogenic or likely pathogenic variants and high-risk clinicopathological factors who had received local treatment and neoadjuvant or adjuvant chemotherapy. Patients were randomly assigned (in a 1:1 ratio) to 1 year of oral olaparib or placebo. The primary end point was invasive disease-free survival. RESULTS: A total of 1836 patients underwent randomization. At a prespecified event-driven interim analysis with a median follow-up of 2.5 years, the 3-year invasive disease-free survival was 85.9% in the olaparib group and 77.1% in the placebo group (difference, 8.8 percentage points; 95% confidence interval [CI], 4.5 to 13.0; hazard ratio for invasive disease or death, 0.58; 99.5% CI, 0.41 to 0.82; P<0.001). The 3-year distant disease-free survival was 87.5% in the olaparib group and 80.4% in the placebo group (difference, 7.1 percentage points; 95% CI, 3.0 to 11.1; hazard ratio for distant disease or death, 0.57; 99.5% CI, 0.39 to 0.83; P<0.001). Olaparib was associated with fewer deaths than placebo (59 and 86, respectively) (hazard ratio, 0.68; 99% CI, 0.44 to 1.05; P = 0.02); however, the between-group difference was not significant at an interim-analysis boundary of a P value of less than 0.01. Safety data were consistent with known side effects of olaparib, with no excess serious adverse events or adverse events of special interest. CONCLUSIONS: Among patients with high-risk, HER2-negative early breast cancer and germline BRCA1 or BRCA2 pathogenic or likely pathogenic variants, adjuvant olaparib after completion of local treatment and neoadjuvant or adjuvant chemotherapy was associated with significantly longer survival free of invasive or distant disease than was placebo. Olaparib had limited effects on global patient-reported quality of life. (Funded by the National Cancer Institute and AstraZeneca; OlympiA ClinicalTrials.gov number, NCT02032823.).
Subject(s)
Antineoplastic Agents/therapeutic use , Breast Neoplasms/drug therapy , Chemotherapy, Adjuvant , Germ-Line Mutation , Phthalazines/therapeutic use , Piperazines/therapeutic use , Poly(ADP-ribose) Polymerase Inhibitors/therapeutic use , Adult , Antineoplastic Agents/adverse effects , Breast Neoplasms/genetics , Breast Neoplasms/mortality , Breast Neoplasms/surgery , Disease-Free Survival , Double-Blind Method , Female , Genes, BRCA1 , Genes, BRCA2 , Humans , Mastectomy , Middle Aged , Phthalazines/adverse effects , Piperazines/adverse effects , Poly(ADP-ribose) Polymerase Inhibitors/adverse effects , Receptor, ErbB-2ABSTRACT
An enhanced understanding of the molecular pathology of disease gained from genomic studies is facilitating the development of treatments that target discrete molecular subclasses of tumours. Considerable associated challenges include how to advance and implement targeted drug-development strategies. Precision medicine centres on delivering the most appropriate therapy to a patient on the basis of clinical and molecular features of their disease. The development of therapeutic agents that target molecular mechanisms is driving innovation in clinical-trial strategies. Although progress has been made, modifications to existing core paradigms in oncology drug development will be required to realize fully the promise of precision medicine.
Subject(s)
Clinical Trials as Topic/methods , Drug Discovery/methods , Medical Oncology/methods , Neoplasms/drug therapy , Precision Medicine/methods , Clinical Trials as Topic/trends , Genetic Testing , Humans , Patient SelectionABSTRACT
BACKGROUND: A high percentage of small cell lung cancer (SCLC) cases harbor cell cycle-related gene mutations and RICTOR amplification. Based on underlying somatic mutations, the authors have conducted a phase 2 biomarker-driven, multiarm umbrella study. METHODS: The SCLC Umbrella Korea StudiES (SUKSES) is an adaptive platform trial that undergoes continual modification according to the observed outcomes. This study included 286 patients with SCLC who failed platinum therapy and who had known genomic profiles based on a predesigned screening trial. Patients with MYC amplification or CDKN2A and TP53 co-alterations were allocated to adavosertib (SUKSES protocol C [SUKSES-C]; 7 patients) and those with RICTOR amplification were allocated to vistusertib (SUKSES-D; 4 patients). Alternatively, patients who were without any predefined biomarkers were assigned to a non-biomarker-selected arm: adavosertib (SUKSES-N1; 21 patients) or AZD2811NP (SUKSES-N3; 15 patients). RESULTS: Patients in the SUKSES-C and SUKSES-N1 arms demonstrated no objective response. Three patients presented with stable disease (SD) in SUKSES-C and 6 patients in SUKSES-N1. The median progression-free survival (PFS) was 1.3 months (95% confidence interval, 0.9 months to not available) for SUKSES-C and 1.2 months (95% CI, 1.1-1.4 months) for SUKSES-N1. Patients in the SUKSES-D arm demonstrated no objective response and no SD, with a PFS of 1.2 months (95% CI, 1.0 months to not available). The SUKSES-N3 arm had 5 patients with SD and a PFS of 1.6 months (95% CI, 0.9-1.7 months), without an objective response. Grade≥3 adverse events (graded according to National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.03]) were observed as follows: 3.2% in the SUKSES-C and SUKSES-N1 arms and 50.0% in the SUKSES-D arm. Target-related neutropenia (grade≥3) was observed in approximately 60.0% of patients in the AZD2811NP arm using the current dosing schedule. CONCLUSIONS: To the best of the authors' knowledge, the current study is the first biomarker-driven umbrella study conducted in patients with recurrent SCLC. Although the current study demonstrated the limited clinical efficacy of monotherapy, novel biomarker approaches using other cell cycle inhibitor(s) or combinations warrant further investigation.
Subject(s)
Cyclin-Dependent Kinase Inhibitor p16/genetics , Neoplasm Recurrence, Local/drug therapy , Proto-Oncogene Proteins c-myc/genetics , Small Cell Lung Carcinoma/drug therapy , Tumor Suppressor Protein p53/genetics , Adult , Aged , Aged, 80 and over , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Benzamides/administration & dosage , Biomarkers, Tumor/genetics , Drug-Related Side Effects and Adverse Reactions , Female , Gene Amplification/drug effects , Humans , Male , Middle Aged , Morpholines/administration & dosage , Neoplasm Recurrence, Local/genetics , Neoplasm Recurrence, Local/pathology , Platinum/adverse effects , Progression-Free Survival , Pyrazoles/administration & dosage , Pyrimidines/administration & dosage , Pyrimidinones/administration & dosage , Rapamycin-Insensitive Companion of mTOR Protein/genetics , Small Cell Lung Carcinoma/genetics , Small Cell Lung Carcinoma/pathologyABSTRACT
Targeted therapies provide clinical benefit and improved therapeutic index. They have a growing prominence in patient management and focus in drug development. Their development is fuelled by our deepening knowledge of complex disease phenotypes and the need for improvement in new therapeutic efficacy. Extrapolation of the biological discovery through to new therapy targeting the causal biological variants to drive clinical gain is challenging. Here, we review the impact of germline mutations on targeted therapies. Historically, germline changes have contributed most to our understanding of disease mechanisms, drug metabolism and exposure, the latter of which has enabled safer positioning of therapies, such as clopidogrel and irinotecan. Similarly, prescreening for germline variants can avoid potentially fatal hypersensitivity reactions with abacavir. However, germline mutations continue to emerge as a central player in targeting therapeutics; ivacaftor drives partial restoration of mucus secretion in cystic fibrosis patients harbouring specific mutations, and treatment with olaparib exploits germline mutations in BRCA genes to drive synthetic lethality as an anti-cancer mechanism. Central is definition of the causal link, association or contribution to the biological variance - and that we believe it is drugable for therapeutic gain. The demand for better therapies to treat modern diseases provides the appetite for continued investigation of the biological variance associated with germline mutations, inevitably leading to increased impact on the development of targeted therapeutics.
Subject(s)
Drug Design , Germ-Line Mutation , Molecular Targeted Therapy , Signal Transduction/drug effects , Signal Transduction/genetics , Animals , Drug-Related Side Effects and Adverse Reactions , Genetic Predisposition to Disease , Humans , Patient Selection , Phenotype , Precision MedicineABSTRACT
PURPOSE: This study reports the safety, tolerability, MTD, recommended phase II dose (RP2D), pharmacokinetic/pharmacodynamic profile, and preliminary antitumor activity of ceralasertib combined with carboplatin in patients with advanced solid tumors. It also examined exploratory predictive and pharmacodynamic biomarkers. PATIENTS AND METHODS: Eligible patients (n = 36) received a fixed dose of carboplatin (AUC5) with escalating doses of ceralasertib (20 mg twice daily to 60 mg once daily) in 21-day cycles. Sequential and concurrent combination dosing schedules were assessed. RESULTS: Two ceralasertib MTD dose schedules, 20 mg twice daily on days 4-13 and 40 mg once daily on days 1-2, were tolerated with carboplatin AUC5; the latter was declared the RP2D. The most common treatment-emergent adverse events (Common Terminology Criteria for Adverse Events grade ≥3) were anemia (39%), thrombocytopenia (36%), and neutropenia (25%). Dose-limiting toxicities of grade 4 thrombocytopenia (n = 2; including one grade 4 platelet count decreased) and a combination of grade 4 thrombocytopenia and grade 3 neutropenia occurred in 3 patients. Ceralasertib was quickly absorbed (tmax â¼1 hour), with a terminal plasma half-life of 8-11 hours. Upregulation of pRAD50, indicative of ataxia telangiectasia mutated (ATM) activation, was observed in tumor biopsies during ceralasertib treatment. Two patients with absent or low ATM or SLFN11 protein expression achieved confirmed RECIST v1.1 partial responses. Eighteen of 34 (53%) response-evaluable patients had RECIST v1.1 stable disease. CONCLUSIONS: The RP2D for ceralasertib plus carboplatin was established as ceralasertib 40 mg once daily on days 1-2 administered with carboplatin AUC5 every 3 weeks, with pharmacokinetic and pharmacodynamic studies confirming pharmacodynamic modulation and preliminary evidence of antitumor activity observed.
Subject(s)
Neoplasms , Neutropenia , Thrombocytopenia , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Ataxia Telangiectasia Mutated Proteins/genetics , Carboplatin , Humans , Indoles , Maximum Tolerated Dose , Morpholines , Neoplasms/etiology , Neutropenia/chemically induced , Nuclear Proteins , Protein Kinase Inhibitors/adverse effects , Pyrimidines , Sulfonamides , Sulfoxides , Thrombocytopenia/chemically inducedABSTRACT
PURPOSE: Some gastric cancers harbor MET gene amplifications that can be targeted by selective MET inhibitors to achieve tumor responses, but resistance eventually develops. Savolitinib, a selective MET inhibitor, is beneficial for treating patients with MET-driven gastric cancer. Understanding the resistance mechanisms is important for optimizing postfailure treatment options. PATIENTS AND METHODS: Here, we identified the mechanisms of acquired resistance to savolitinib in 3 patients with gastric cancer and MET-amplified tumors who showed a clinical response and then cancer progression. Longitudinal circulating tumor DNA (ctDNA) is useful for monitoring resistance during treatment and progression when rebiopsy cannot be performed. RESULTS: Using a next-generation sequencing 100-gene panel, we identified the target mechanisms of resistance MET D1228V/N/H and Y1230C mutations or high copy number MET gene amplifications that emerge when resistance to savolitinib develops in patients with MET-amplified gastric cancer. CONCLUSION: We demonstrated the utility of ctDNA in gastric cancer and confirmed this approach using baseline tumor tissue or rebiopsy.
ABSTRACT
MET amplification is a frequently observed genomic aberration in solid tumors. We conducted a phase I trial to evaluate dose-limiting toxicity (DLT) and recommended phase II dose (RP2D) for the combination therapy. The following dose levels were tested in this single-arm phase I study: docetaxel as an intravenous infusion over 1â¯hour at 60â¯mg/m2 once every 3â¯weeks of a 21-day schedule plus savolitinib (level 1, 200â¯mg qd; level 2, 400â¯mg qd; level 3, 600â¯mg qd; level 4800â¯mg qd). In total, there were 17 patients enrolled on to this study [7 gastric cancer (GC) patients, 5 melanoma patients, 3 sarcoma patients, and 2 rectal cancer patients]. Most of the patients (14 of 17) were heavily pretreated (≥third line or greater lines of treatment). For the first 3 cohorts (200â¯mg savolitinib + docetaxel 60â¯mg/m2, 400â¯mg savolitinib + docetaxel 60 mg/m2, 600â¯mg savolitinib + docetaxel 60â¯mg/m2), there were no DLTs. In the fourth dose cohort (800â¯mg savolitinib + docetaxel 60â¯mg/m2), one DLT occurred with generalized edema grade 3 that required intensive management. One GC patient with both MET overexpression (3+) and MET amplification (MET/CEP7 ratio, 7.3) achieved a durable partial response for 297â¯days, and another MET-amplified GC patient (MET/CEP7 ratio, 7.6) achieved stable disease for 86â¯days. Due to the higher incidence of G4 neutropenia in cohort 4 (800 mg), we recommend savolitinib 600â¯mg qd in combination with docetaxel 60â¯mg/m2 as the RP2D for phase II trial. The combination therapy demonstrated a very promising antitumor activity with durable responses in MET amplified GC patients.
ABSTRACT
DNA-dependent protein kinase (DNA-PK) is a critical player in the DNA damage response (DDR) and instrumental in the non-homologous end-joining pathway (NHEJ) used to detect and repair DNA double-strand breaks (DSBs). We demonstrate that the potent and highly selective DNA-PK inhibitor, AZD7648, is an efficient sensitizer of radiation- and doxorubicin-induced DNA damage, with combinations in xenograft and patient-derived xenograft (PDX) models inducing sustained regressions. Using ATM-deficient cells, we demonstrate that AZD7648, in combination with the PARP inhibitor olaparib, increases genomic instability, resulting in cell growth inhibition and apoptosis. AZD7648 enhanced olaparib efficacy across a range of doses and schedules in xenograft and PDX models, enabling sustained tumour regression and providing a clear rationale for its clinical investigation. Through its differentiated mechanism of action as an NHEJ inhibitor, AZD7648 complements the current armamentarium of DDR-targeted agents and has potential in combination with these agents to achieve deeper responses to current therapies.
Subject(s)
Apoptosis/drug effects , Cell Proliferation/drug effects , DNA-Activated Protein Kinase/antagonists & inhibitors , Drug Synergism , Protein Kinase Inhibitors/pharmacology , Purines/pharmacology , Pyrans/pharmacology , Radiation Tolerance/drug effects , Triazoles/pharmacology , A549 Cells , Animals , Antibiotics, Antineoplastic/pharmacology , Carcinoma, Non-Small-Cell Lung , Cell Line, Tumor , Doxorubicin/analogs & derivatives , Doxorubicin/pharmacology , Genomic Instability/drug effects , Humans , Lung Neoplasms , Mice , Phthalazines/pharmacology , Piperazines/pharmacology , Poly(ADP-ribose) Polymerase Inhibitors/pharmacology , Polyethylene Glycols/pharmacology , Radiotherapy , Xenograft Model Antitumor AssaysABSTRACT
The VIKTORY (targeted agent eValuation In gastric cancer basket KORea) trial was designed to classify patients with metastatic gastric cancer based on clinical sequencing and focused on eight different biomarker groups (RAS aberration, TP53 mutation, PIK3CA mutation/amplification, MET amplification, MET overexpression, all negative, TSC2 deficient, or RICTOR amplification) to assign patients to one of the 10 associated clinical trials in second-line (2L) treatment. Capivasertib (AKT inhibitor), savolitinib (MET inhibitor), selumetinib (MEK inhibitor), adavosertib (WEE1 inhibitor), and vistusertib (TORC inhibitor) were tested with or without chemotherapy. Seven hundred seventy-two patients with gastric cancer were enrolled, and sequencing was successfully achieved in 715 patients (92.6%). When molecular screening was linked to seamless immediate access to parallel matched trials, 14.7% of patients received biomarker-assigned drug treatment. The biomarker-assigned treatment cohort had encouraging response rates and survival when compared with conventional 2L chemotherapy. Circulating tumor (ctDNA) analysis demonstrated good correlation between high MET copy number by ctDNA and response to savolitinib. SIGNIFICANCE: Prospective clinical sequencing revealed that baseline heterogeneity between tumor samples from different patients affected response to biomarker-selected therapies. VIKTORY is the first and largest platform study in gastric cancer and supports both the feasibility of tumor profiling and its clinical utility.This article is highlighted in the In This Issue feature, p. 1325.
Subject(s)
Biomarkers, Tumor , Genomics , Stomach Neoplasms/genetics , Stomach Neoplasms/pathology , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Biopsy , Circulating Tumor DNA , Clinical Decision-Making , Computational Biology/methods , Disease Management , Gene Expression Profiling , Gene Expression Regulation, Neoplastic/drug effects , Genomics/methods , Humans , Molecular Targeted Therapy , Neoplasm Metastasis , Neoplasm Staging , Prognosis , Stomach Neoplasms/drug therapy , Stomach Neoplasms/mortality , Treatment OutcomeABSTRACT
The neuropeptide Neuromedin U (NMU) stimulates smooth muscle contraction, and modulates local blood flow and adrenocortical function via two endogenous receptors, NMU1 and NMU2. Although its amino-acid sequence is highly conserved across species, the physiological effects of NMU are variable between species and little is known of its effects on human tissues. We have examined the contractile effects of NMU-25 on human smooth muscles of the gastrointestinal (GI) tract (ascending colon, gallbladder) and long saphenous vein (LSV) using in vitro organ bath bioassays. From LSV, ileum, gallbladder, caecum and colon, NMU receptor transcripts were amplified by RT-PCR and expression levels were determined by semi-quantitative scanning densitometry. NMU-25 produced a concentration-dependent, sustained contraction of isolated smooth muscle (p[A](50)+/-s.e.m., ascending colon, 8.93+/-0.18; gallbladder, 7.01+/-0.15; LSV, 8.67+/-0.09). NMU1 and NMU2 receptor transcription was detected in all tissues; transcription of both receptors was similar in gallbladder, but NMU1 receptor transcription was predominant in the sigmoid colon and LSV. In summary, these studies indicate that NMU may control tone in the human GI tract and LSV through an action on smooth muscle. Development of NMU receptor subtype-selective ligands will aid the further elucidation of the physiological roles of NMU and its two receptors.
Subject(s)
Muscle, Smooth/pathology , Neuropeptides/pharmacology , Saphenous Vein/pathology , Colon/metabolism , Densitometry , Gallbladder/metabolism , Humans , Intestinal Mucosa/metabolism , Muscle Contraction , Muscle, Smooth/metabolism , Neuropeptides/chemistry , Neuropeptides/metabolism , RNA/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Transcription, GeneticABSTRACT
Genomic profiling of tumours in patients in clinical trials enables rapid testing of multiple hypotheses to confirm which genomic events determine likely responder groups for targeted agents. A key challenge of this new capability is defining which specific genomic events should be classified as 'actionable' (that is, potentially responsive to a targeted therapy), especially when looking for early indications of patient subgroups likely to be responsive to new drugs. This Opinion article discusses some of the different approaches being taken in early clinical development to define actionable mutations, and describes our strategy to address this challenge in early-stage exploratory clinical trials.
Subject(s)
Carcinoma, Non-Small-Cell Lung/drug therapy , Lung Neoplasms/drug therapy , Mutation , Carcinoma, Non-Small-Cell Lung/genetics , Humans , Lung Neoplasms/genetics , Pyrazoles/therapeutic use , Pyrimidines/therapeutic use , Pyrimidinones , Tumor Suppressor Protein p53/geneticsABSTRACT
A rapid expansion in precision medicine founded on the potential for durable clinical benefit through matching a drug to a predictive marker used to select patients has driven the development of targeted drugs with accompanied companion diagnostics for patient selection. Oncology has been at the forefront, with the improvements in patient survival notable. Increasing numbers of molecular subgroups require an equally increasing number (and new generation) of highly selective agents targeting inevitably lower incidence molecular segments, posing significant challenges for drug development. Innovative trial designs (umbrella or basket studies) are emerging as patient-centric approaches and public-private partnerships, cross-industry, government and non-profit sector collaborations are enabling implementation. Success will require continued innovation, new paradigms in oncology drug development and market approval and continued collaboration.
Subject(s)
Neoplasms/drug therapy , Drug Discovery/methods , Drug Industry/methods , Humans , Medical Oncology/methods , Precision Medicine/methodsABSTRACT
The drivers of precision medicine are clear: for patients (and physicians)--more options, durable clinical benefit, reduced exposure to non-effective drugs and potential to leverage current scientific and technological advances; for the pharmaceutical industry--the potential to tackle core challenges in discovering and developing better and more efficacious medicines, to reduce rates of attrition in drug development and to reduce development costs; for healthcare systems and payers--improved efficiency through the provision of effective care and avoiding ineffective treatments. Oncology has been at the vanguard, the improvements gained in patient survival notable. However, the increasing number of molecular subgroups requires an equally increasing number (and new generation) of highly selective agents targeting inevitably lower incidence molecular segments. Innovative trial designs (umbrella/basket studies) are emerging as a patient-centric approach to drug development, and the rise in public-private partnerships, cross-industry, government and non-profit sector collaborations is enabling implementation of complex clinical trial designs. This poses significant challenges for healthcare systems and regulatory approval. Further substantial evolution of policy and processes, particularly regulatory requirements for approval for new therapeutics, are required.
Subject(s)
Drug Discovery , Medical Oncology/methods , Precision Medicine/methods , Clinical Trials as Topic/methods , Cooperative Behavior , Drug Approval , Drug Discovery/economics , Drug Discovery/trends , Drug Industry/economics , Humans , Molecular Targeted Therapy , Patient Selection , Precision Medicine/trends , Public-Private Sector PartnershipsABSTRACT
Digital ring block anesthesia, which is frequently used before surgery for ingrown toenails, is often extremely uncomfortable for patients and can be the most distressing aspect of the procedure. The authors used a novel needleless injection device to induce digital anesthesia before surgery and compared it in terms of patient discomfort and preference with use of a standard needle and syringe for injection in individuals undergoing simultaneous bilateral nail procedures. Use of the needleless device significantly reduced the pain associated with this procedure and was preferred over use of a standard needle and syringe by all individuals. Other potential advantages of a needleless injection system are discussed.
Subject(s)
Anesthesia, Local/instrumentation , Injections/methods , Nails, Ingrown/surgery , Nerve Block/instrumentation , Adolescent , Adult , Aged , Humans , Injections/adverse effects , Middle Aged , Pain/etiologyABSTRACT
OBJECTIVES: To help clarify the controversy over the detection of expression of the cholecystokinin 1 receptor (CCK1R; CCKAR) in human pancreas. METHODS: Applied qRT-PCR to detect CCK1R expression using the SYBR green/Smart Cycler II and the QZyme oligonucleotide/ABI PRISM 7500 systems to detect CCK1R expressed message in highly purified cDNAs from human pancreas and other tissues. Samples of normal pancreas were obtained at operation (pancreaticoduodenectomy; Whipple's procedure) and used to ascertain the expression of CCK1R in human tissue and investigate donor individual variability in expression levels by semi-quantitative RT-PCR and scanning densitometry. RESULTS: We present molecular evidence obtained with advanced qRT-PCR technology that clearly establishes CCK1R expression in human pancreas. Amplification variation in individual human samples is documented here. By targeting different stretches of the sequence with several primer pairs, it was observed that SYBR green qRT-PCR failed to amplify efficiently over GGA-and GAA-rich nucleotide triplet regions, leading to false negative results. The QZyme system quantified the expression with the following distribution: stomach > small intestine approximately colon > brain approximately kidney > pancreas. CCK1R expression levels varied from undetectable, to high levels of expression, in individual samples collected from surgical specimens. CONCLUSION: CCK1R message can be conclusively detected and quantified in human pancreas cDNA by targeting the appropriate nucleotide sequence regions of this gene.
Subject(s)
Pancreas/metabolism , Receptor, Cholecystokinin A/genetics , Reverse Transcriptase Polymerase Chain Reaction/methods , DNA, Complementary/genetics , HumansABSTRACT
BACKGROUND AND OBJECTIVES: Colorectal cancers (CRC) with high-level micro-satellite instability (MSI-H) show reduced metastatic potential and better prognosis compared to stage-matched stable (MSS) cancers. Angiogenesis/lymphangiogenesis, central to tumour growth and spread, is mediated by vascular endothelial growth factor (VEGF) cytokines, but little is known of their relationship to MSI. METHODS: In this study, 67 sporadic CRC with identified MSI status, and 8 samples of normal colon were analysed for VEGF-A soluble isoforms (VEGF-121/VEGF-165) and VEGF-C gene transcription (by RT-PCR and scanning densitometry), and blood vessel density (BVD; measuring angiogenesis) and VEGF-C protein expression (measuring lymphangiogenesis). RESULTS: Compared to normal colon, VEGF-165 transcription was reduced (P < 0.05), but VEGF-121 transcription was higher in MSS (P < 0.06) and MSI-L (P < 0.01) cancers (but similar in MSI-H). VEGF-165 transcription was unrelated to MSI, but VEGF-121 transcription was elevated in MSI-L (P < 0.06). There was a weak inverse correlation with VEGF-121 transcription and Dukes stage (P < 0.09), and with BVD and MSI (P < 0.09). With a singular di-nucleotide loci mutation (MSI-L), VEGF-121 (P < 0.03) and VEGF-C (P < 0.04) transcription was elevated. CONCLUSIONS: MSI-H cancers have reduced angiogenic/lymphangiogenic potential, and transcription of VEGF-121 may be important in early growth and spread of CRC. Elevated VEGF-121 and VEGF-C transcription with singular di-nucleotide mutations may aid in the identification of distinct MSI-L cancers.