Emerging role of liquid biopsy in rat sarcoma virus mutated metastatic colorectal cancer:A case report

BACKGROUND In patients with metastatic colorectal cancer(mCRC),the treatment options are limited and have been proved to be affected by rat sarcoma virus(RAS)mutational status.In RAS wild-type(wt)patients,the combination of antiepidermal growth factor receptor(EGFR)monoclonal antibodies with chemotherapy(CT)is more effective than CT alone.On the other hand,RAS-mutated patients are not eligible for treatment with anti-EGFR antibodies.CASE SUMMARY Eleven patients with initially RAS-mutated mCRC were followed from diagnosis to May 2022.At the time of cell-free DNA determination,five patients had undergone one CT line,five patients had undergone two CT lines,and one patient had undergone three CT lines(all in combination with bevacizumab).At the second and third treatment lines[second line(2L),third line(3L)],patients with neo-RAS wt received a combination of CT and cetuximab.In neo-RAS wt patients treated with anti-EGFR,our findings indicated an increase in progression-free survival for both 2L and 3L(14.5 mo,P=0.119 and 3.9 mo,P=0.882,respectively).Regarding 2L overall survival,we registered a slight increase in neo-RAS wt patients treated with anti-EGFR(33.6 mo vs 32.4 mo,P=0.385).At data cut-off,two patients were still alive:A RAS-mutated patient undergoing 3L treatment and a neo-RAS wt patient who received 2L treatment with anti-EGFR(ongoing).CONCLUSION Our case series demonstrated that monitoring RAS mutations in mCRC by liquid biopsy may provide an additional treatment line for neo-RAS wt patients.

Novel synthetic opioids-toxicological aspects and analysis

Over the past few years,there has been an emerging number of new psychoactive drugs.These drugs are frequently mentioned as“legal highs”,“herbal highs”,“bath salts”and“research chemicals”.They are mostly sold and advertised on online forums and on the dark web.The emerging new psychoactive substances are designed to mimic the effects of psychoactive groups,which are often abused drugs.Novel synthetic opioids are a new trend in this context and represent an alarming threat to public health.Given the wide number of fatalities related to these compounds reported within the last few years,it is an important task to accurately identify these compounds in biologic matrices in order to administer an effective treatment and reverse the respiratory depression caused by opioid related substances.Clinicians dealing with fentanyl intoxication cases should consider that it could,in fact,be a fentanyl analogue.For this reason,it is a helpful recommendation to include synthetic opioids in the routine toxicological screening procedures,including analysis in alternative matrices,if available,to investigate poly-drug use and possible tolerance to opioids.To address this public health problem,better international collaboration,effective legislation,effective investigation,control of suspicious“research chemicals”online forums and continuous community alertness are required.This article aims to review diverse reported fatalities associated with new synthetic opioids describing them in terms of pharmacology,metabolism,posology,available forms,as well as their toxic effects,highlighting the sample procedures and analytical techniques available for their detection and quantification in biological matrices.