Abstract:The standard of care in locally advanced rectal cancer is neoadjuvant chemoradiation (nCRT) followed by radical surgery. Response to nCRT varies among patients and pathological complete response is associated with better outcome. However, there is a lack of effective methods to select rectal cancer patients who would or would not have a benefit from nCRT. The utility of clinicopathological and radiological features are limited due to lack of adequate sensitivity and specificity. Molecular biomarkers have the potential to predict response to nCRT at an early time point, but none have currently reached the clinic. Integration of diverse types of biomarkers including clinicopathological and imaging features, identification of mechanistic link to tumor biology, and rigorous validation using samples which represent disease heterogeneity, will allow to develop a sensitive and cost-effective molecular biomarker panel for precision medicine in rectal cancer. Here, we aim to review the recent advance in tissue-and blood-based molecular biomarker research and illustrate their potential in predicting nCRT response in rectal cancer.

Background With the goal of discovering non-invasive biomarkers for early diagnosis of GC, we conducted a case-control study utilising urine samples from individuals with predominantly early GC vs. healthy control (HC). Methods Among urine samples from 372 patients, age- and sex-matched 282 patients were randomly divided into three groups: 18 patients in a discovery cohort; 176 patients in a training cohort and 88 patients in a validation cohort. Results Among urinary proteins identified in the comprehensive quantitative proteomics analysis, urinary levels of TFF1 (uTFF1) and ADAM12 (uADAM12) were significantly independent diagnostic biomarkers for GC, in addition to Helicobacter pylori status. A urinary biomarker panel combining uTFF1, uADAM12 and H. pylori significantly distinguished between HC and GC patients in both training and validation cohorts. On the analysis for sex-specific biomarkers, this combination panel demonstrated a good AUC of 0.858 for male GC, whereas another combination panel of uTFF1, uBARD1 and H. pylori also provided a good AUC of 0.893 for female GC. Notably, each panel could distinguish even stage I GC patients from HC patients (AUC = 0.850 for males; AUC = 0.845 for females). Conclusions Novel urinary protein biomarker panels represent promising non-invasive biomarkers for GC, including early-stage disease.

Epidermal growth factor receptor (EGFR) is a cell surface receptor that has an essential role in cell proliferation and survival, and overexpression of EGFR is a common feature of human cancers. In Non-small-cell lung cancer (NSCLC), activating mutations of EGFR have also been described. We recently showed that mutant EGFR-L858R inhibits the expression of the p14ARF tumor-suppressor protein to promote cell survival. In this study, we defined the molecular bases by which EGFR controls Arf expression. Using various lung tumor models, we showed that EGF stimulation inhibits Arf transcription by a mechanism involving the nuclear transport and recruitment of EGFR to the Arf promoter. We unraveled the vesicular trafficking protein Vps34 as a mediator of EGFR nuclear trafficking and showed that its neutralization prevents the accumulation of EGFR to the Arf promoter in response to ligand activation. Finally, in lung tumor cells that carry mutant EGFR-L858R, we demonstrated that inhibition of Vps34 using small interfering RNA restrains nuclear EGFR location and restores Arf expression leading to apoptosis. These findings identify the Arf tumor suppressor as a new transcriptional target of nuclear EGFR and highlight Vps34 as an important regulator of the nuclear EGFR/Arf survival pathway. As a whole, they provide a mechanistic explanation to the inverse correlation between nuclear expression of EGFR and overall survival in NSCLC patients.