Are we making progress in diagnosing and preventing gastrointestinal cancers?

Prognostic value of HIF-1α in digestive system malignancies: evidence from a systematic review and meta-analysis

Aim

This meta-analysis aimed to evaluate the association of HIF-1α expression with clinicopathological features and overall survival (OS) of patients with digestive system malignancies.

Background

Numerous studies have demonstrated that hypoxia-inducible factor-1α (HIF-1α) is abnormally expressed in various solid tumors. However, the clinicopathological features and prognostic value of HIF-1α expression in patients with digestive system malignancies remain controversial.

Methods

A literature search in PubMed, Web of Science, and Scopus databases was performed to identify all relevant studies published in English until 15 October 2020. The pooled effect was calculated to evaluate the association between HIF-1α expression and clinicopathological features and overall survival in cancer patients. Pooled odds ratios (ORs) or hazard ratios (HRs) with a 95% confidence interval (CI) were calculated using fixed- or random-effects model based on between-study heterogeneity.

Results

A total of 44 eligible studies with 5,964 patients were included. The pooled results indicated a positive association of HIF-1α overexpression with poor overall survival (OS) (HR=1.990, 95% CI: 1.615-2.453, p<0.001) and disease-free survival (DFS) (HR=1.90, 95% CI: 1.084-3.329, p=0.043). Meta-analysis results showed that HIF-1α level expression was significantly associated with positive lymph node metastasis (OR=1.869, 95% CI: 1.488-2.248, p<0.001), distance metastasis (OR=2.604, 95% CI: 1.500-4.519, p<0.001), tumor stage (OR=1.801, 95% CI: 1.437-2.257, p<0.001) and tumor size (OR=1.392. 95% CI: 1.068-1.815, p=0.014).

Conclusion

This meta-data suggest that HIF-1α expression might serve as an independent prognostic marker and a promising therapeutic target in patients with digestive system malignancies.

Long Noncoding RNAs in Digestive System Malignancies: A Novel Class of Cancer Biomarkers and Therapeutic Targets?

High throughput methodologies have revealed the existence of an unexpectedly large number of long noncoding RNAs (lncRNAs). The unconventional role of lncRNAs in gene expression regulation and their broad implication in oncogenic and tumor suppressive pathways have introduced lncRNAs as novel biological tumor markers. The most prominent example of lncRNAs application in routine clinical practice is PCA3, a FDA-approved biomarker for prostate cancer. Regarding digestive system malignancies, the oncogenic HOTAIR is one of the most widely studied lncRNAs in the preclinical level and has already been identified as a potent prognostic marker for major malignancies of the gastrointestinal tract. Here, we provide an overview of recent findings regarding the emerging role of lncRNAs not only as key regulators of cancer initiation and progression in colon, stomach, pancreatic, liver, and esophageal cancers, but also as reliable tumor markers and therapeutic tools. lncRNAs can be easily, rapidly, and cost-effectively determined in tissues, serum, and gastric juice, making them highly versatile analytes. Taking also into consideration the largely unmet clinical need for early diagnosis and more accurate prognostic/predictive markers for gastrointestinal cancer patients, we comment upon the perspectives of lncRNAs as efficient molecular tools that could aid in the clinical management.

Autofluorescence endoscopy with "real-time" digital image processing in differential diagnostics of selected benign and malignant lesions in the oesophagus

BACKGROUND

Oesophageal papilloma and Barrett's oesophagus are benign lesions known as risk factors of carcinoma in the oesophagus. Therefore, it is important to diagnose these early changes before neoplastic transformation.

METHOD

Autofluorescence endoscopy is a fast and non-invasive method of imaging of tissues based on the natural fluorescence of endogenous fluorophores. The aim of this study was to prove the diagnostic utility of autofluorescence endoscopy with digital image processing in histological diagnosis of endoscopic findings in the upper digestive tract, primarily in the imaging of oesophageal papilloma.

RESULTS

During the retrospective analysis of about 200 endoscopic procedures in the upper digestive tract, 67 cases of benign, precancerous or cancerous changes were found. White light endoscopy (WLE) image, single-channel (red or green) autofluorescence images, as well as green and red fluorescence intensities in two modal fluorescence image and red-to-green (R/G) ratio (Numerical Colour Value, NCV) were correlated with histopathologic results. The NCV analysis in autofluorescence imaging (AFI) showed increased R/G ratio in cancerous changes in 96% vs. 85% in WLE. Simultaneous analysis with digital image processing allowed us to diagnose suspicious tissue as cancerous in all of cases. Barrett's metaplasia was confirmed in 90% vs. 79% (AFI vs. WLE), and 98% in imaging with digital image processing. In benign lesions, WLE allowed us to exclude tissue as malignant in 85%. Using autofluorescence endoscopy R/G ratio was increased in only 10% of benign changes causing the picture to be interpreted as suspicious, but when both methods were used together, 97.5% were cases excluded as malignancies. Mean R/G ratios were estimated to be 2.5 in cancers, 1.25 in Barrett's metaplasia and 0.75 in benign changes and were statistically significant (p=0.04).

CONCLUSION

Autofluorescence imaging is a sensitive method to diagnose precancerous and cancerous early stages of the diseases located in oesophagus. Especially in two-modal imaging including white light endoscopy, autofluorescence imaging with digital image processing seems to be a useful modality of early diagnostics. Also in observation of papilloma changes, it facilitates differentiation between neoplastic and benign lesions and more accurate estimation of the risk of potential malignancy.