James M. Allan

Loci on 7p12.2, 10q21.2 and 14q11.2 are associated with risk of childhood acute lymphoblastic leukemia

To identify risk variants for childhood acute lymphoblastic leukemia (ALL), we conducted a genome-wide association study of two case-control series, analyzing the genotypes with respect to 291,423 tagging SNPs in a total of 907 ALL cases and 2,398 controls. We identified risk loci for ALL at 7p12.2 (IKZF1, rs4132601, odds ratio (OR) = 1.69, P = 1.20 × 10−19), 10q21.2 (ARID5B, rs7089424, OR = 1.65, P = 6.69 × 10−19) and 14q11.2 (CEBPE, rs2239633, OR = 1.34, P = 2.88 × 10−7). The 10q21.2 (ARID5B) risk association appears to be selective for the subset of B-cell precursor ALL with hyperdiploidy. These data show that common low-penetrance susceptibility alleles contribute to the risk of developing childhood ALL and provide new insight into disease causation of this specific hematological cancer. Notably, all three risk variants map to genes involved in transcriptional regulation and differentiation of B-cell progenitors.

A genome-wide association study identifies six susceptibility loci for chronic lymphocytic leukemia

We conducted a genome-wide association study of 299,983 tagging SNPs for chronic lymphocytic leukemia (CLL) and performed validation in two additional series totaling 1,529 cases and 3,115 controls. We identified six previously unreported CLL risk loci at 2q13 (rs17483466; P = 2.36 × 10−10), 2q37.1 (rs13397985, SP140; P = 5.40 × 10−10), 6p25.3 (rs872071, IRF4; P = 1.91 × 10−20), 11q24.1 (rs735665; P = 3.78 × 10−12), 15q23 (rs7176508; P = 4.54 × 10−12) and 19q13.32 (rs11083846, PRKD2; P = 3.96 × 10−9). These data provide the first evidence for the existence of common, low-penetrance susceptibility to a hematological malignancy and new insights into disease causation in CLL.

Polymorphism in glutathione S-transferase P1 is associated with susceptibility to chemotherapy-induced leukemia

Glutathione S-transferases (GSTs) detoxify potentially mutagenic and toxic DNA-reactive electrophiles, including metabolites of several chemotherapeutic agents, some of which are suspected human carcinogens. Functional polymorphisms exist in at least three genes that encode GSTs, including GSTM1, GSTT1, and GSTP1. We hypothesize, therefore, that polymorphisms in genes that encode GSTs alter susceptibility to chemotherapy-induced carcinogenesis, specifically to therapy-related acute myeloid leukemia (t-AML), a devastating complication of long-term cancer survival. Elucidation of genetic determinants may help to identify individuals at increased risk of developing t-AML. To this end, we have examined 89 cases of t-AML, 420 cases of de novo AML, and 1,022 controls for polymorphisms in GSTM1, GSTT1, and GSTP1. Gene deletion of GSTM1 or GSTT1 was not specifically associated with susceptibility to t-AML. Individuals with at least one GSTP1 codon 105 Val allele were significantly over-represented in t-AML cases compared with de novo AML cases [odds ratio (OR), 1.81; 95% confidence interval (CI), 1.11–2.94]. Moreover, relative to de novo AML, the GSTP1 codon 105 Val allele occurred more often among t-AML patients with prior exposure to chemotherapy (OR, 2.66; 95% CI, 1.39–5.09), particularly among those with prior exposure to known GSTP1 substrates (OR, 4.34; 95% CI, 1.43–13.20), and not among those t-AML patients with prior exposure to radiotherapy alone (OR,1.01; 95% CI, 0.50–2.07). These data suggest that inheritance of at least one Val allele at GSTP1 codon 105 confers a significantly increased risk of developing t-AML after cytotoxic chemotherapy, but not after radiotherapy.

Mechanisms of therapy-related carcinogenesis

Therapy-related cancers, defined as second primary cancers that arise as a consequence of chemotherapy and/or radiotherapy, are unusual in that they have a well-defined aetiology. Knowledge of the specific nature of the initiating exposure and exactly when it occurred has made it easier to identify crucial genetic events and to model these in vitro and in vivo. As such, the study of therapy-related cancers has led to the elucidation of discrete mechanisms of carcinogenesis, including DNA double-strand-break-induced gene translocation and genomic instability conferred by loss of DNA repair. Unsurprisingly, some of these mechanisms seem to operate in the development of sporadic cancers.

Common variants at 2q37.3, 8q24.21, 15q21.3 and 16q24.1 influence chronic lymphocytic leukemia risk

To identify new risk variants for chronic lymphocytic leukemia (CLL), we conducted a genome-wide association study of 299,983 tagging SNPs, with validation in four additional series totaling 2,503 cases and 5,789 controls. We identified four new risk loci for CLL at 2q37.3 (rs757978, FARP2; odds ratio (OR) = 1.39; P = 2.11 × 10−9), 8q24.21 (rs2456449; OR = 1.26; P = 7.84 × 10−10), 15q21.3 (rs7169431; OR = 1.36; P = 4.74 × 10−7) and 16q24.1 (rs305061; OR = 1.22; P = 3.60 × 10−7). We also found evidence for risk loci at 15q25.2 (rs783540, CPEB1; OR = 1.18; P = 3.67 × 10−6) and 18q21.1 (rs1036935; OR = 1.22; P = 2.28 × 10−6). These data provide further evidence for genetic susceptibility to this B-cell hematological malignancy.

Testicular Cancer Survivorship: Research Strategies and Recommendations

Testicular cancer represents the most curable solid tumor, with a 10-year survival rate of more than 95%. Given the young average age at diagnosis, it is estimated that effective treatment approaches, in particular, platinum-based chemotherapy, have resulted in an average gain of several decades of life. This success, however, is offset by the emergence of considerable long-term morbidity, including second malignant neoplasms, cardiovascular disease, neurotoxicity, nephrotoxicity, pulmonary toxicity, hypogonadism, decreased fertility, and psychosocial problems. Data on underlying genetic or molecular factors that might identify those patients at highest risk for late sequelae are sparse. Genome-wide association studies and other translational molecular approaches now provide opportunities to identify testicular cancer survivors at greatest risk for therapy-related complications to develop evidence-based long-term follow-up guidelines and interventional strategies. We review research priorities identified during an international workshop devoted to testicular cancer survivors. Recommendations include 1) institution of lifelong follow-up of testicular cancer survivors within a large cohort setting to ascertain risks of emerging toxicities and the evolution of known late sequelae, 2) development of comprehensive risk prediction models that include treatment factors and genetic modifiers of late sequelae, 3) elucidation of the effect(s) of decades-long exposure to low serum levels of platinum, 4) assessment of the overall burden of medical and psychosocial morbidity, and 5) the eventual formulation of evidence-based long-term follow-up guidelines and interventions. Just as testicular cancer once served as the paradigm of a curable malignancy, comprehensive follow-up studies of testicular cancer survivors can pioneer new methodologies in survivorship research for all adult-onset cancer.

Variation in CDKN2A at 9p21.3 influences childhood acute lymphoblastic leukemia risk

Using data from a genome-wide association study of 907 individuals with childhood acute lymphoblastic leukemia (cases) and 2,398 controls and with validation in samples totaling 2,386 cases and 2,419 controls, we have shown that common variation at 9p21.3 (rs3731217, intron 1 of CDKN2A) influences acute lymphoblastic leukemia risk (odds ratio = 0.71, P = 3.01 × 10−11), irrespective of cell lineage.

Second Malignant Neoplasms and Cardiovascular Disease Following Radiotherapy

Second malignant neoplasms (SMNs) and cardiovascular disease (CVD) are among the most serious and life-threatening late adverse effects experienced by the growing number of cancer survivors worldwide and are due in part to radiotherapy. The National Council on Radiation Protection and Measurements (NCRP) convened an expert scientific committee to critically and comprehensively review associations between radiotherapy and SMNs and CVD, taking into account radiobiology; genomics; treatment (ie, radiotherapy with or without chemotherapy and other therapies); type of radiation; and quantitative considerations (ie, dose-response relationships). Major conclusions of the NCRP include: 1) the relevance of older technologies for current risk assessment when organ-specific absorbed dose and the appropriate relative biological effectiveness are taken into account and 2) the identification of critical research needs with regard to newer radiation modalities, dose-response relationships, and genetic susceptibility. Recommendation for research priorities and infrastructural requirements include 1) long-term large-scale follow-up of extant cancer survivors and prospectively treated patients to characterize risks of SMNs and CVD in terms of radiation dose and type; 2) biological sample collection to integrate epidemiological studies with molecular and genetic evaluations; 3) investigation of interactions between radiotherapy and other potential confounding factors, such as age, sex, race, tobacco and alcohol use, dietary intake, energy balance, and other cofactors, as well as genetic susceptibility; 4) focusing on adolescent and young adult cancer survivors, given the sparse research in this population; and 5) construction of comprehensive risk prediction models for SMNs and CVD to permit the development of follow-up guidelines and prevention and intervention strategies.

Association of Molecular Markers With Toxicity Outcomes in a Randomized Trial of Chemotherapy for Advanced Colorectal Cancer: The FOCUS Trial

PURPOSE Predicting efficacy and toxicity could potentially allow individualization of cancer therapy. We investigated putative pharmacogenetic markers of chemotherapy toxicity in a large randomized trial. PATIENTS, MATERIALS, AND METHODS Patients were randomly assigned to different sequences of chemotherapy for advanced colorectal cancer. First-line therapy was fluorouracil (FU), irinotecan/FU (IrFU) or oxaliplatin/FU (OxFU). Patients allocated first-line FU had planned second-line irinotecan alone, IrFU, or OxFU. The primary toxicity outcome measure was toxicity-induced delay or dose reduction; the secondary outcome was Common Terminology Criteria of Adverse Events grade >or= 3 toxicity. DNA was analyzed in 1,188 patients; 1,036 were assessable for the primary outcome, including 688 treated with FU, 270 with IrFU (first or second line), 280 with OxFU (first or second line), 184 with irinotecan alone, and 454 with any irinotecan-containing regimen. Ten polymorphisms were assessed: thymidylate synthase-enhancer region (TYMS-ER), thymidylate synthase 1494 (TYMS-1494), dihydropyrimidine dehydrogenase (DPYD), methylenetetrahydrofolate reductase (MTHFR), mutL homolog 1 (MLH1), UDP glucuronyltransferase (UGT1A1), ATP-binding cassette group B gene 1 (ABCB1), x-ray cross-complementing group 1 (XRCC1), glutathione-S-transferase P1 (GSTP1), and excision repair cross-complementing gene 2 (ERCC2). Results Using the primary outcome measure, no polymorphism was significantly associated (P < .01) with the toxicity of any regimen or with the difference in toxicity of IrFU or OxFU versus FU alone. Trends (of doubtful significance) were seen for associations of XRCC1, ERCC2, and GSTP1 with toxicity during irinotecan regimens: XRCC1, primary end point, any irinotecan-containing regimen (P = .045); ERCC2, secondary end point, irinotecan alone (P = .003); GSTP1, secondary end point; IrFU (P = .039); and irinotecan alone (P = .05). There was no evidence of association of UGT1A1*28 with irinotecan toxicity. CONCLUSION These results do not support the routine clinical use of the evaluated polymorphisms, including UGT1A1*28. Further investigation of XRCC1, ERCC2, and GSTP1 as potential predictors of irinotecan toxicity is warranted.

Carbon-13 CP/MAS spectroscopy of coal macerals

Abstract 13 C n.m.r. spectra of kerogen concentrates isolated from several different subbituminous to high-volatile bituminous coal macerals have been obtained by a combined cross polarization/magic-angle spinning technique. The samples comprise three vitrinites, two sporinites, two alginites and one fusinite, all of Upper Paleozoic age. It is shown that this technique can be used to differentiate the maceral types by providing characteristic spectral fingerprints. Aromaticities decrease in the order fusinite vitrinite sporinite alginite, as expected with the rank range studied. Furthermore, fine spectral details provide general information on the nature and distribution of discrete structural moieties and their variations with both type and rank.