Exploiting novel molecular targets in gastrointestinal cancers

Novel molecular targets are being discovered as we learn more about the aberrant processes underlying various cancers. Efforts to translate this knowledge are starting to impact on the care of patients with gastrointestinal cancers. The epidermal growth factor receptor (EGFR) pathway and angiogenesis have been targeted successfully in colorectal cancer with cetuximab, panitunumab and bevacizumab. Similarly, EGFR-targeting with erlotinib yielded significant survival benefit in pancreatic cancer when combined with gemcitabine. The multi-targeting approach with sorafenib has made it the first agent to achieve significant survival benefit in hepatocellular carcinoma. Efforts to exploit the dysregulated Akt/mTOR pathway in GI cancer therapy are ongoing. These molecular targets can be disrupted by various approaches, including the use of monoclonal antibody to intercept extracellular ligands and disrupt receptor-ligand binding, and small molecule inhibitors that interrupt the activation of intracellular kinases.

Approach to early-onset colorectal cancer:Clinicopathological,familial,molecular and immunohistochemical characteristics

AIM:To characterize clinicopathological and familial features of early-onset colorectal cancer(CRC) and compare features of tumors with and without microsatellite instability(MSI).METHODS:Forty-five patients with CRC aged 45 or younger were included in the study.Clinical information,a three-generation family history,and tumor samples were obtained.MSI status was analyzed and mismatch repair genes were examined in the MSI families.Tumors were included in a tissue microarray and an immunohistochemical study was carried out with a panel of selected antibodies.RESULTS:Early onset CRC is characterized by advanced stage at diagnosis,right colon location,low-grade of differentiation,mucin production,and presence of polyps.Hereditary forms represent at least 21% of cases.Eighty-one percent of patients who died during followup showed a lack of expression of cyclin E,which could be a marker of poor prognosis.β-catenin expression was normal in a high percentage of tumors.CONCLUSION:Early-onset CRC has an important familial component,with a high proportion of tumors showing microsatellite stable.Cyclin E might be a poor prognosis factor.

New approach to assess sperm DNA fragmentation dynamics： Fine-tuning mathematical models

Background： Sperm DNA fragmentation（sDF） has been proved to be an important parameter in order to predict in vitro the potential fertility of a semen sample. Colloid centrifugation could be a suitable technique to select those donkey sperm more resistant to DNA fragmentation after thawing. Previous studies have shown that to elucidate the latent damage of the DNA molecule, sDF should be assessed dynamically, where the rate of fragmentation between treatments indicates how resistant the DNA is to iatrogenic damage. The rate of fragmentation is calculated using the slope of a linear regression equation. However, it has not been studied if s DF dynamics fit this model. The objectives of this study were to evaluate the effect of different after-thawing centrifugation protocols on sperm DNA fragmentation and elucidate the most accurate mathematical model（linear regression, exponential or polynomial） for DNA fragmentation over time in frozen-thawed donkey semen.Results： After submitting post-thaw semen samples to no centrifugation（UDC）, sperm washing（SW） or single layer centrifugation（SLC） protocols, sD F values after 6 h of incubation were significantly lower in SLC samples than in SW or UDC.Coefficient of determination（R-2） values were significantly higher for a second order polynomial model than for linear or exponential. The highest values for acceleration of fragmentation（aSDF） were obtained for SW, fol owed by SLC and UDC.Conclusion： SLC after thawing seems to preserve longer DNA longevity in comparison to UDC and SW. Moreover,the fine-tuning of models has shown that sDF dynamics in frozen-thawed donkey semen fit a second order polynomial model, which implies that fragmentation rate is not constant and fragmentation acceleration must be taken into account to elucidate hidden damage in the DNA molecule.