E.C. Zwarthoff

Distinct gene mutation profiles among luminal-type and basal-type breast cancer cell lines.

Breast cancer has for long been recognized as a highly diverse tumor group, but the underlying genetic basis has been elusive. Here, we report an extensive molecular characterization of a collection of 41 human breast cancer cell lines. Protein and gene expression analyses indicated that the collection of breast cancer cell lines has retained most, if not all, molecular characteristics that are typical for clinical breast cancers. Gene mutation analyses identified 146 oncogenic mutations among 27 well-known cancer genes, amounting to an average of 3.6 mutations per cell line. Mutations in genes from the p53, RB and PI3K tumor suppressor pathways were widespread among all breast cancer cell lines. Most important, we have identified two gene mutation profiles that are specifically associated with luminal-type and basal-type breast cancer cell lines. The luminal mutation profile involved E-cadherin and MAP2K4 gene mutations and amplifications of Cyclin D1, ERBB2 and HDM2, whereas the basal mutation profile involved BRCA1, RB1, RAS and BRAF gene mutations and deletions of p16 and p14ARF. These subtype-specific gene mutation profiles constitute a genetic basis for the heterogeneity observed among human breast cancers, providing clues for their underlying biology and providing guidance for targeted pharmacogenetic intervention in breast cancer patients.

Outcomes of a Bladder Cancer Screening Program Using Home Hematuria Testing and Molecular Markers

BACKGROUNDnWe previously reported the preliminary findings from a feasibility study of bladder cancer (BCa) screening with urinary molecular markers (Bladder Cancer Urine Marker Project [BLU-P]) that has now been terminated.nnnOBJECTIVEnTo report the final results from BLU-P to determine whether mass screening for BCa is feasible and useful.nnnDESIGN, SETTING, AND PARTICIPANTSnBLU-P was a Dutch population-based study initiated in 2008 to evaluate BCa screening. A total of 6500 men were invited to participate in the study, 1984 (30.5%) agreed, and 1747 (88.1%) men completed the protocol and were followed for 2 yr.nnnINTERVENTIONnThe screening protocol included home hematuria testing followed by molecular markers-nuclear matrix protein 22 (NMP22), microsatellite analysis (MA), fibroblast growth factor receptor 3 (FGFR3) mutation snapshot assay, and a custom methylation-specific (MLPA) test-to determine the need for cystoscopy.nnnOUTCOME MEASUREMENTS AND STATISTICAL ANALYSISnOutcomes included the number of cystoscopies and the cancer detection rate within and outside the protocol, as determined by linkage to national registries.nnnRESULTS AND LIMITATIONSnOverall, 409 men (23.4%) tested positive for hematuria and underwent molecular testing. Current smokers (n=295 [17%]) and past smokers (n=998 [58%]) were significantly more likely to test positive for hematuria than nonsmokers. Seventy-one of 75 men (94.6%) with positive molecular markers underwent the recommended cystoscopy. Four BCas and one kidney tumor were detected through this sequential protocol, whereas one BCa and one kidney tumor were missed through the screening program. Limitations include the possibility of healthy subject bias.nnnCONCLUSIONSnFor BCa screening, use of a sequential protocol with home hematuria testing followed by molecular markers substantially reduced the number of cystoscopy recommendations compared with dipstick testing alone. A sequential screening approach may help minimize unnecessary invasive follow-up testing, with very few missed cancers. Nevertheless, this mass screening program had a very low diagnostic yield in an unselected asymptomatic European male population.

Evidence for two candidate tumour suppressor loci on chromosome 9q in transitional cell carcinoma (TCC) of the bladder but no homozygous deletions in bladder tumour cell lines.

SummaryThe most frequent genetic alterations in transitional cell carcinoma (TCC) of the bladder involve loss of heterozygosity (LOH) on chromosome 9p and 9q. The LOH on chromosome 9p most likely targets the CDKN2 locus, which is inactivated in about 50% of TCCs. Candidate genes that are the target for LOH on chromosome 9q have yet to be identified. To narrow the localization of one or more putative tumour suppressor genes on this chromosome that play a role in TCC of the bladder, we examined 59 tumours with a panel of microsatellite markers along the chromosome. LOH was observed in 26 (44%) tumours. We present evidence for two different loci on the long arm of chromosome 9 where potential tumour suppressor genes are expected. These loci are delineated by interstitial deletions in two bladder tumours. Our results confirm the results of others and contribute to a further reduction of the size of these regions, which we called TCC1 and TCC2. These regions were examined for homozygous deletions with EST and STS markers. No homozygous deletions were observed in 17 different bladder tumour cell lines.

1104 FGFR3 mutation analysis in voided urine samples to decrease cystoscopies and cost in nonmuscle invasive bladder cancer surveillance: A comparison of 3 strategies

Purpose: We determined whether FGFR3 mutation analysis of voided urine samples would be cost-effective to partly replace cystoscopy in the surveillance of patients treated for nonmuscle invasive urothelial carcinoma.Materials and Methods: In this decision analytical study we analyzed data on 70 Dutch patients with FGFR3 positive primary tumors and a median followup of 8.8 years. Surveillance strategies were compared in a Markov model. Modified surveillance consisted of FGFR3 mutation analysis of voided urine samples every 3 months, and cystoscopy at 3, 12 and 24 months. Standard surveillance was defined as cystoscopy every 3 months and minimal surveillance was defined as cystoscopy at 3, 12 and 24 months. Analysis was stratified for 3 risk profiles, including surveillance after 1) the primary tumor, 2) the first to third recurrence and 3) the fourth recurrence or more. Sensitivity analysis was performed to evaluate the impact of variations in cost, sensitivity and specificity.Results: The probability of n...