Plasma KRAS mutations predict the early recurrence after surgical resection of pancreatic cancer.

BACKGROUND: The technique to analyze circulating tumor DNA (ctDNA) in body fluid (so-called "liquid biopsy") is recently developed. AIMS: Our aim was to assess the utility of liquid biopsy for predicting progression of pancreatic ductal adenocarcinoma (PDAC) after surgical resection or chemotherapy. METHODS: A total of 72 patients with PDAC were retrospectively enrolled for this study, 33 treated surgically and 39 given chemotherapy, either FOLFIRINOX (oxaliplatin/irinotecan/fluorouracil/leucovorin) or gemcitabine plus nab-paclitaxel. Prior to treatment, patients were screened for the presence of KRAS mutations (G12D and G12V) in plasma using droplet digital polymerase chain reaction, and outcomes were compared. RESULTS: KRAS mutations were identified in plasma samples of 12 patients (36%) underwent surgical resection. Patients with plasma KRAS mutations had significantly shorter disease-free survival (DFS) and overall survival (p < .01 and p = .01, respectively). Of 10 clinical variables analyzed, plasma KRAS mutation was the factor predictive of DFS in multivariate analysis (RR = 3.58, 95% CI: 1.36-9.60; p = .01). Although 12 patients (31%) given chemotherapy tested positive for plasma KRAS mutations, there was no demonstrable relation between plasma KRAS mutations and progression-free survival (PFS) or overall survival (OS) (p = .35 and p = .68, respectively). CONCLUSIONS: In patients with PDAC, detection of KRAS mutations in plasma proved independently predictive of early recurrence after surgical resection but did not correlate with PFS following chemotherapy.

Detachment of a prosthetic valve due to infective endocarditis caused by Streptococcus pneumoniae.

The incidence of infective endocarditis (IE) due to S pneumoniae has decreased, thanks to antibiotics. However, when it does occur, it can be lethal. The present case provides a reminder of the potential lethality of this postoperative infection.

Utility of serum DNA as a marker for KRAS mutations in pancreatic cancer tissue.

BACKGROUND/OBJECTIVES: The detection of cancer-specific DNA in peripheral blood, known as a liquid biopsy, has been reported recently. Most such studies have used plasma as a sample; however, whether or not serum can be used as effectively is unclear. We attempted to clarify suitable samples for detecting KRAS mutations in circulating DNA in the blood of pancreatic cancer patients using droplet digital polymerase chain reaction (PCR). METHODS: DNA was extracted from the tissue, plasma, and serum of 40 pancreatic cancer patients. The presence of KRAS mutations G12D, G12V, and G12R was analyzed by droplet digital PCR. RESULTS: The amount of DNA isolated from the serum was much higher than that from plasma (1.0- to 42.0-fold). At least 1 KRAS mutation was observed in 93% of cancer tissues, whereas we detected the mutations in only 48% of the serum and plasma DNA samples. The G12D mutation was the most prevalent of the three mutations, followed by the G12V mutation. The presence of the G12D KRAS mutation in the plasma, serum, or tissue did not correlate to the overall survival; however, the prognosis of the patients with a KRAS mutation at G12V in the plasma or serum was significantly poorer than that of the patients without the mutation (P < 0.01). CONCLUSIONS: Serum and plasma were found to be good materials for detecting cancer-specific DNA in the peripheral blood and the presence of KRAS mutations in blood-derived DNA may be used as a prognostic biomarker for patients with pancreatic cancer.