Differences according to educational level in the management and survival of colorectal cancer in Sweden

Socioeconomic status (SES) affects survival after a cancer diagnosis. The extent to which differences in management can explain this is not known. Record-linkage between two Swedish Regional Clinical Quality Registers of colorectal cancer and a socio-economic database generated a dataset with information on diagnostic procedures, treatment and survival in patients of different educational background. Three thousand eight hundred and ninety-nine rectal cancer patients from the years 1995 to 2006 and 5715 colon cancer patients from 1997 to 2006 were evaluated. Compared to patients with high education, those with shorter education had poorer relative and overall survival (57.9% 5-year relative survival versus 63.8% in colon cancer, 58.7% versus 69.1% in rectal cancer). There were also differences in diagnostic activity with preoperative computer tomography (40% versus 47.3%) and colonoscopy (56.3% versus 62.8%) being more frequent in highly educated groups (p = 0.001 and 0.037, respectively). Surgery resulting in colostomy was performed in 26.9% of rectal cancer patients of high education compared to 35.5% of those with low education (p = 0.005). Although rectal cancer has poorer prognosis than colon cancer, it was noted that among the highly educated, rectal cancer patients had better survival than colon cancer patients (69.1% versus 63.8% 5-year relative survival). It thus appears that improved rectal cancer management has benefited mainly patients of middle and higher educational levels. We conclude that socioeconomic differences exist in diagnostic activity and management of colorectal cancer, which may affect survival.     

HMGA2 and MDM2 expression in lipomatous tumors with partial, low-level amplification of sequences from the long arm of chromosome 12

Ordinary lipomas are cytogenetically characterized primarily by simple balanced chromosome aberrations with stable morphologies, most of which affect chromosome segment, 12q13-15, where the HMGA2 gene plays a key pathogenetic role. Atypical lipomatous tumors (ALTs) display supernumerary ring or giant marker chromosomes with amplification of several genes including HMGA2 and MDM2. A study of HMGA2 expression in a variety of adipocytic tumors showed aberrant expression in lipomas with 12q13-15 aberrations and ring chromosomes as well as in ALTs and well-differentiated liposarcomas (WDLSs), and frequent differential expression of HMGA2 exons 1-2 versus that of exons 4-5. A minor subset of adipocytic tumors harbors unbalanced karyotypes with extra copies of 12q sequences in structures that are not giant marker or ring chromosomes. Out of a series of ten such tumors, three lipomas and four ALTs with more than two copies of 12q13-15 and breakpoints in 12q13-15 could be analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) to find out whether HMGA2 and MDM2 expression was more similar to the levels seen in lipomas with cytogenetically balanced aberrations of 12q13-15, or to ALTs with giant ring or marker chromosomes. One of two ALTs with more complex, hyperdiploid karyotypes had expression levels closer to those seen in ALT, whereas the remaining six cases were similar to lipomas with 12q13-15 changes and ring chromosomes. Differential expression was seen in two ALTs and all three lipomas. Two cases showed MDM2 expression levels similar to those found among WDLSs, two cases showed levels similar to those found among lipomas, whereas the remaining three cases displayed intermediate expression levels. The studied cases represent intermediates between lipoma and ALT, insofar as they?shared 12q13-15 rearrangements and karyotypic stability with lipomas and gain of 12q sequences with ALTs. Neither of these characteristics can be used to discriminate between lipoma and ALT.     

Fibronectin 1 is a potential biomarker for radioresistance in head and neck squamous cell carcinoma

Radiotherapy remains the backbone of head and neck cancer therapy but response is sometimes impeded by tumor radioresistance. Identifying predictive biomarkers of radiotherapy response is a crucial step towards personalized therapy. The aim of this study was to explore gene expression data in search of biomarkers predictive of the response to radiotherapy in head and neck squamous cell carcinoma (HNSCC). Microarray analysis was performed on five cell lines with various intrinsic radiosensitivity, selected from a panel of 29 HNSCC cell lines. The bioinformatics approach included Gene Ontology (GO) enrichment profiling and Ingenuity Pathway Analysis (IPA). The GO-analysis detected 16 deregulated categories from which development, receptor activity, and extracellular region represented the largest groups. Fourteen hub genes (CEBPA, CEBPB, CTNNB1, FN1, MYC, MYCN, PLAU, SDC4, SERPINE1, SP1, TAF4B, THBS1, TP53 and VLDLR) were identified from the IPA network analysis. The hub genes in the highest ranked network, (FN1, SERPINE1, THBS1 and VLDLR) were further subjected to qPCR analysis in the complete panel of 29 cell lines. Of these genes, high FN1 expression associated to high intrinsic radiosensitivity (p=0.047). In conclusion, gene ontologies and hub genes of importance for intrinsic radiosensitivity were defined. The overall results suggest that FN1 should be explored as a potential novel biomarker for radioresistance.     

Temporal trends in the proportion cured among adults diagnosed with acute myeloid leukaemia in Sweden 1973–2001, a population‐based study

Large age‐dependant differences in temporal trends in 1‐ and 5‐year relative survival have been observed in patients with acute myeloid leukaemia (AML) in Sweden. This investigation used an alternative approach to studying patient survival that simultaneously estimated the proportion of patients cured from their cancer and the survival of the ‘uncured’. We conducted a population‐based study including 6439 AML patients aged 19–80 years in Sweden between 1973 and 2001. Mixture cure models were estimated, with age at diagnosis categorised (19–40, 41–60, 61–70 and 71–80) and year of diagnosis modelled using splines. In 1975 the cure proportion was ≤6% in all age groups and the median survival time for ‘uncured’ patients was <0·5 years. In 2000 the cure proportion was 68% (95% confidence interval 56–77%) in the youngest group, and 32% (25–39%), 8% (3–21%), and 4% (2–8%) in the other groups, respectively. The median survival times for ‘uncured’ were 0·74 (0·43–1·26), 0·71 (0·53–0·97), 0·69 (0·51–0·95) and 0·37 (0·31–0·44) years, respectively. A dramatic improvement in the cure proportion was seen in younger patients, whereas improvement in older ages was mainly within the survival of the ‘uncured’. This novel approach of analysing survival data could be a valuable tool for physicians, patients, health care planners and health economists.     

Generation of trisomies in cancer cells by multipolar mitosis and incomplete cytokinesis

One extra chromosome copy (i.e., trisomy) is the most common type of chromosome aberration in cancer cells. The mechanisms behind the generation of trisomies in tumor cells are largely unknown, although it has been suggested that dysfunction of the spindle assembly checkpoint (SAC) leads to an accumulation of trisomies through failure to correctly segregate sister chromatids in successive cell divisions. By using Wilms tumor as a model for cancers with trisomies, we now show that trisomic cells can form even in the presence of a functional SAC through tripolar cell divisions in which sister chromatid separation proceeds in a regular fashion, but cytokinesis failure nevertheless leads to an asymmetrical segregation of chromosomes into two daughter cells. A model for the generation of trisomies by such asymmetrical cell division accurately predicted several features of clones having extra chromosomes in vivo, including the ratio between trisomies and tetrasomies and the observation that different trisomies found in the same tumor occupy identical proportions of cells and colocalize in tumor tissue. Our findings provide an experimentally validated model explaining how multiple trisomies can occur in tumor cells that still maintain accurate sister chromatid separation at metaphase-anaphase transition and thereby physiologically satisfy the SAC.     

Longitudinal evidence for diminished frontal cortex function in aging

Cross-sectional estimates of age-related changes in brain structure and function were compared with 6-y longitudinal estimates. The results indicated increased sensitivity of the longitudinal approach as well as qualitative differences. Critically, the cross-sectional analyses were suggestive of age-related frontal overrecruitment, whereas the longitudinal analyses revealed frontal underrecruitment with advancing age. The cross-sectional observation of overrecruitment reflected a select elderly sample. However, when followed over time, this sample showed reduced frontal recruitment. These findings dispute inferences of true age changes on the basis of age differences, hence challenging some contemporary models of neurocognitive aging, and demonstrate age-related decline in frontal brain volume as well as functional response.