Molecular genetics of early-onset colorectal cancer

Early-onset colorectal cancer (EOCRC) has been rising in global prevalence and incidence over the past several decades. Environmental influences, including generational lifestyle changes and rising obesity, contribute to these increased rates. While the rise in EOCRC is best documented in western countries, it is seen throughout the world, although EOCRC may have distinct genetic mutations in patients of different ethnic backgrounds. Pathological and molecular characterizations show that EOCRC has a distinct presentation compared with later-onset colorectal cancer (LOCRC). Recent studies have identified DNA, RNA, and protein-level alterations unique to EOCRC, revealing much-needed biomarkers and potential novel therapeutic targets. Many molecular EOCRC studies have been performed with Caucasian and Asian EOCRC cohorts, however, studies of other ethnic backgrounds are limited. In addition, certain molecular characterizations that have been conducted for LOCRC have not yet been repeated in EOCRC, including high-throughput analyses of histone modifications, mRNA splicing, and proteomics on large cohorts. We propose that the complex relationship between cancer and aging should be considered when studying the molecular underpinnings of EOCRC. In this review, we summarize current EOCRC literature, focusing on sporadic molecular alterations in tumors, and their clinical implications. We conclude by discussing current challenges and future directions of EOCRC research efforts.

The relationship between surgical site drains and reoperation for wound-related complications following posterior cervical spine surgery: a multicenter retrospective study

OBJECTIVE

Use of surgical site drains following posterior cervical spine surgery is variable, and its impact on outcomes remains controversial. Studies of drain use in the lumbar spine have suggested that drains are not associated with reduction of reoperations for wound infection or hematoma. There is a paucity of studies examining this relationship in the cervical spine, where hematomas and infections can have severe consequences. This study aims to examine the relationship between surgical site drains and reoperation for wound-related complications following posterior cervical spine surgery.

METHODS

This study is a multicenter retrospective review of 1799 consecutive patients who underwent posterior cervical decompression with instrumentation at 4 tertiary care centers between 2004 and 2016. Demographic and perioperative data were analyzed for associations with drain placement and return to the operating room.

RESULTS

Of 1799 patients, 1180 (65.6%) had a drain placed. Multivariate logistic regression analysis identified history of diabetes (OR 1.37, p = 0.03) and total number of levels operated (OR 1.32, p < 0.001) as independent predictors of drain placement. Rates of reoperation for any surgical site complication were not different between the drain and no-drain groups (4.07% vs 3.88%, p = 0.85). Similarly, rates of reoperation for surgical site infection (1.61% vs 2.58%, p = 0.16) and hematoma (0.68% vs 0.48%, p = 0.62) were not different between the drain and no-drain groups. However, after adjusting for history of diabetes and the number of operative levels, patients with drains had significantly lower odds of returning to the operating room for surgical site infection (OR 0.48, p = 0.04) but not for hematoma (OR 1.22, p = 0.77).

CONCLUSIONS

This large study characterizes current practice patterns in the utilization of surgical site drains during posterior cervical decompression and instrumentation. Patients with drains placed did not have lower odds of returning to the operating room for postoperative hematoma. However, the authors’ data suggest that patients with drains may be less likely to return to the operating room for surgical site infection, although the absolute number of infections in the entire population was small, limiting the analysis.

Probing charge transfer dynamics in a single iron tetraphenylporphyrin dyad adsorbed on an insulating surface

Although the dynamics of charge transfer (CT) processes can be probed with ultimate lifetime resolution, the inability to control CT at the nanoscale is one of the most important roadblocks to revealing some of its deep fundamental aspects. In this work, we present an investigation of CT dynamics in a single iron tetraphenylporphyrin (Fe-TPP) donor/acceptor dyad adsorbed on a CaF2/Si(100) insulating surface. The tip of a scanning tunneling microscope (STM) is used to create local ionic states in one fragment of the dyad. The CT process is monitored by imaging subsequent changes in the neighbor acceptor molecule and its efficiency is mapped, revealing the influence of the initial excited state in the donor molecule. In the validation of the experiments, simulations based on density functional theory show that holes have a higher donor-acceptor CT rate compared to electrons and highlight a noticeable initial state dependence on the CT process. We leverage the unprecedented spatial resolution achieved in our experiments to show that the CT process in the dyad is governed via molecule-molecule coherent tunneling with negligible surface-mediated character.