Molecular testing for lymph node metastases as a determinant of colon cancer recurrence: results from a retrospective multicenter study.

PURPOSE: Recurrence risk assessment to make treatment decisions for early-stage colon cancer patients is a major unmet medical need. The aim of this retrospective multicenter study was to evaluate the clinical utility of guanylyl cyclase C (GCC) mRNA levels in lymph nodes on colon cancer recurrence. METHODS: The proportion of lymph nodes with GCC-positive mRNA (LNR) was evaluated in 463 untreated T3N0 patients, blinded to clinical outcomes. One site's (n = 97) tissue grossing method precluded appropriate lymph node assessment resulting in post hoc exclusion. Cox regression models tested the relationship between GCC and the primary endpoint of time to recurrence. Assay methods, primary analyses, and cut points were all prespecified. RESULTS: Final dataset contained 366 patients, 38 (10%) of whom had recurrence. Presence of four or more GCC-positive lymph nodes was significantly associated with risk of recurrence [hazard ratio (HR) = 2.46, 95% confidence interval (CI), 1.07-5.69, P = 0.035], whereas binary GCC LNR risk class (HR = 1.87, 95% CI, 0.99-3.54, P = 0.054) and mismatch repair (MMR) status (HR = 0.77, 95% CI, 0.36-1.62, P = 0.49) were not. In a secondary analysis using a 3-level GCC LNR risk group classification of high (LNR > 0.20), intermediate (0.10 < LNR ≤ 0.20), and low (LNR ≤ 0.10), high-risk patients had a 2.5 times higher recurrence risk compared with low-risk patients (HR = 2.53, 95% CI, 1.24-5.17, P = 0.011). CONCLUSIONS: GCC status is a promising prognostic factor independent of traditional histopathology risk factors in a contemporary population of patients with stage IIa colon cancer not treated with adjuvant therapy, but GCC determination must be performed with methodology adapted to the tissue procurement and fixation technique.

Scientific horizons in cancer control: genomes, informatics and personalized medicine.

The goals of cancer control are to reduce cancer risk, detect cancers earlier, improve treatments and enhance the health of cancer survivors. Personalized medicine aims to customize health care by tailoring care to the individual patient using genetic and other information. This review considers the traditional strengths of Connecticut's cancer control program as well as trends in emerging science, primarily under development through the auspices of the National Cancer Institute's Division of Cancer Control and Population Sciences. It focuses on resources for cancer control offered by the Connecticut Tumor Registry in addition to opportunities for improving cancer control through developments in informatics and cancer genomics. It provides an overview of the use of informatic tools, electronic health records, health information exchange, integration of genotyping into risk models, and genomic analyses of clinical tumor specimens, demonstrating how the common theme in these advances will lead toward more personalized cancer control.

5,10-methylenetetrahydrofolate reductase (MTHFR) polymorphisms and the risk of acute lymphoblastic leukemia (ALL) in Filipino children.

BACKGROUND: 5,10-Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme in folate metabolism. Polymorphisms at the C677T and A1298C loci are associated with reduced activity; consequently more folate substrates are shunted toward thymidylate and DNA synthesis. Several studies have reported a reduced risk of developing ALL in children with MTHFR polymorphisms. The objective of this study was to determine the association between MTHFR polymorphisms and ALL in Filipino children. PROCEDURE: We conducted a case control study in children diagnosed with ALL at the Philippine General Hospital from 1/2001 through 12/2005. Bone marrow aspirate slides were reviewed by two expert hematologists to verify the morphologic diagnosis of ALL. DNA was isolated from the slides and MTHFR polymorphisms, C677T and A1298C, were determined using Taqman real-time PCR. Cord blood of healthy Filipino newborns served as control. RESULTS: There were a total of 191 ALL and 394 controls genotyped. The distribution of C677T polymorphisms was similar in the two groups (P = 1.0). However, for A1298C, there was significantly more AC and CC genotypes in the ALL compared to controls (P = 0.02; OR 1.57; CI: 1.08-2.28). The 1298C allele frequency for the control group was 36.8% and 677T allele frequency was 9.9%. CONCLUSION: A1298C polymorphisms is associated with an increased risk for ALL in Filipino children. This may be due to a difference in leukemia biology or to a high prevalence of folate deficiency in Filipinos. Our study reiterates the gene and environment interaction in leukemogenesis.

Transcriptional profiling of degraded RNA in cryopreserved and fixed tissue samples obtained at autopsy.

BACKGROUND: Traditional multiplexed gene expression methods require well preserved, intact RNA. Such specimens are difficult to acquire in clinical practice where formalin fixation is the standard procedure for processing tissue. Even when special handling methods are used to obtain frozen tissue, there may be RNA degradation; for example autopsy samples where degradation occurs both pre-mortem and during the interval between death and cryopreservation. Although specimens with partially degraded RNA can be analyzed by qRT-PCR, these analyses can only be done individually or at low levels of multiplexing and are laborious and expensive to run for large numbers of RNA targets. METHODS: We evaluated the ability of the cDNA-mediated Annealing, Selection, extension, and Ligation (DASL) assay to provide highly multiplexed analyses of cryopreserved and formalin fixed, paraffin embedded (FFPE) tissues obtained at autopsy. Each assay provides data on 1536 targets, and can be performed on specimens with RNA fragments as small as 60 bp. RESULTS: The DASL performed accurately and consistently with cryopreserved RNA obtained at autopsy as well as with RNA extracted from formalin-fixed paraffin embedded tissue that had a cryopreserved mirror image specimen with high quality RNA. In FFPE tissue where the cryopreserved mirror image specimen was of low quality the assay performed reproducibly on some but not all specimens. CONCLUSION: The DASL assay provides reproducible results from cryopreserved specimens and many FFPE specimens obtained at autopsy. Gene expression analyses of these specimens may be especially valuable for the study of non-cancer endpoints, where surgical specimens are rarely available.

Impact of a genetic variant in CYP3A4 on risk and clinical presentation of prostate cancer among white and African-American men.

Genes involved in androgen metabolism are strong candidates for having an important role in the pathogenesis of prostate cancer. CYP3A4, a protein in the cytochrome P-450 supergene family, facilitates the oxidative deactivation of testosterone. In previous studies, patients with the G variant of a genetic polymorphism in CYP3A4 had prostate cancers with clinically aggressive characteristics at diagnosis. The association was strongest among elderly men. We investigated whether the CYP3A4 variant was linked with the diagnosis or clinical presentation of prostate cancer in a case control study of a multiethnic urban population. Biologic specimens were genotyped for CYP3A4, and analyzed for the impact of this genotype on risk and tumor characteristics at presentation, controlling for the effect of several cofactors. The CYP3A4 variant was more common among African-Americans than among white men. Race-stratified analyses revealed little association between the CYP3A4 variant and prostate cancer risk among white men but were limited by the small number of white men with the CYP3A4 variant. Of African-American men, while the variant G allele was not associated with prostate cancer that had less aggressive characteristics, it was associated with risk of aggressive prostate cancer when men with the AG genotype (odds ratio = 9.3, 95% confidence interval 1.3-411) or GG genotype (odds ratio = 11.9 95% confidence interval 1.6-533) were compared with those with the AA genotype. The association between the CYP3A4 genotype and aggressive prostate cancer in African-American men is consistent with findings of other studies.

The impact of CAG repeats in exon 1 of the androgen receptor on disease progression after prostatectomy.

BACKGROUND: The authors examined the impact of the number of CAG repeats in exon 1 of the androgen receptor on disease progression among men with prostate carcinoma after prostatectomy. This polymorphism has been associated with alterations in activity of the androgen receptor in in vitro systems and with the risk of clinically diagnosed prostate carcinoma in some epidemiologic studies. An earlier series found that, among men at low risk of progressive disease, a small number of CAG repeats predicted a high risk of recurrence, and the impact of CAG repeats varied among men with different risks of progressive disease. METHODS: The authors analyzed specimens from a large clinical series of fixed tissue specimens from men who underwent prostatectomy at a single institution, including 413 American white men (WM) and 298 African-American men (AAM), with 5-10 years of available clinical follow-up. RESULTS: There was little association between the number of CAG repeats and extent of disease, Gleason score, and preoperative PSA level at diagnosis. Overall, patients who had > 18 CAG repeats had a greater risk of recurrence compared with patients who had 18 CAG repeats had an estimated 52% increased risk of disease recurrence. The increased risk could be attributed to men who were at high risk of recurrence.

CYP3A4 genetic variant and disease-free survival among white and black men after radical prostatectomy.

PURPOSE: Prostate cancer is an androgen sensitive disease. Cytochrome P450 3A4 (CYP3A4) oxidatively deactivates testosterone by converting it to biologically less active metabolites. Previous studies suggest that a germline genetic variant in the 5' regulatory region of the gene may interfere with deactivation and increase the risk of clinically advanced prostate cancer. We investigated the impact of this polymorphism on the risk of recurrence after prostatectomy. MATERIALS AND METHODS: We assembled clinical data and analyzed specimens from a large series of patients who underwent prostatectomy who were carefully staged at a single institution and had 5 to 10 years of prospective clinical followup. The series included 428 white men and 309 black men. RESULTS: Stage, Gleason score or preoperative prostate specific antigen strongly predicted progression-free survival (PFS) but were not associated with CYP3A4 genotypes. There was a strong association between race and genotype (p = 0.00002) in that 8% of white men and 83% of black men had 1 or more copies of the G allele. When both races were included genotype was associated with PFS (hazard ratio [HR] 1.27, CI 1.08-1.27, p = 0.005). In race specific analyses increasing copies of the G allele were associated with poorer PFS among white men (HR 1.98, CI 1.06-3.70, p = 0.03) but had little impact on PFS among black men (HR 1.004, CI 0.77-1.32, p = 0.97). CONCLUSIONS: The CYP3A4 genotype studied was not associated with pathological features of prostate cancer for men of either race. Unstratified analyses of men of both races and stratified analyses of white men demonstrated poorer PFS after prostatectomy for those with the G allele, but the G allele did not predict PFS among black men.

Vitamin D receptor gene polymorphisms and disease free survival after radical prostatectomy.

BACKGROUND: Vitamin D has been linked with prostate cancer risk in epidemiologic studies and has antiproliferative, prodifferentiation, and antimetastatic properties in experimental systems. Its hormonal activity is mediated by the vitamin D receptor. We investigated whether germ-line genetic variation in the vitamin D receptor impacts progression of prostate cancer after radical prostatectomy. METHODS: We analyzed BsmI and TaqI polymorphisms using archived specimens from a large series of radical prostatectomy patients at a single institution. Our series included 428 white men (WM) and 310 African-American men (AAM) who were carefully and uniformly staged and followed for 5-10 years. RESULTS: The distribution of polymorphisms varied between WM and AAM. There was little association between genotype and extent of disease at diagnosis, Gleason score, preoperative PSA, or recurrence overall. Among WM with locally advanced disease, however, the BsmI B allele protected against recurrence in models examining gene dose (P = 0.04) and dominant effects (P = 0.05). CONCLUSIONS: Overall vitamin D receptor polymorphisms did not predict pathologic features of prostate cancer but may impact on risk of recurrence among men in certain risk groups. Analysis of polymorphisms may provide clues about the mechanisms through which vitamin D exerts its inhibitory effects on prostate cancer in vivo in men.