BACKGROUND: CA 19-9 is a commonly assessed tumor marker, considered characteristic of pancreatic ductal adenocarcinoma (PDAC) and biliary tract cancers; however, the positive predictive value of CA 19.9 is too low, and the usage of CA 19.9 as a screening tool in the healthy population remains controversial.
METHODS: The presented case illustrates a reversed diagnosis of highly elevated serum CA 19-9 levels in a 54-year-old female complaining of pain in the epigastric region, shortly after COVID-19 vaccination. Laboratory tests showed a significantly elevated level of the CA 19-9 marker (>12,000 U/mL, reference value: <37 U/mL) with normal pancreatic enzyme activity. The patient underwent imaging examination, which showed no abnormalities, except for increased pancreatic dimension and areas of fluid signal in the pancreas in magnetic resonance imaging (MRI), which may correspond to autoimmune pancreatitis (AIP). The patient remains asymptomatic with a recommendation for a follow-up MRI in 12 months.
RESULTS: A literature review conducted revealed multi-causal CA 19-9 increases above 1000 U/mL, including non-cancerous diseases of the lung, pancreas, liver, ovary, kidney, and others. The median concentration of CA 19-9 regardless of the cause of disease was 2810 U/mL (IQR ± 6895). The median CA 19-9 values in men and women were 3500 (IQR ± 10,050) and 2455 (IQR ± 3927), respectively, and differ significantly between the compared groups (p < 0.05). There was no difference between CA 19-9 values and the categorized cause of the increase.
CONCLUSIONS: Conducting differential diagnosis, it should not be forgotten that most international guidelines recommend the use of CA 19-9 only in conjunction with pathology of pancreas in radiological imaging; however, even such a combination can point the diagnostic pathway in the wrong direction. A highly elevated CA 19-9 level, typically associated with PDAC, may be the result of benign disease including AIP related to COVID-19 vaccination.

UNASSIGNED: Therapeutic possibilities for non-small cell lung cancer (NSCLC) have considerably increased during recent decades.
UNASSIGNED: To summarize the prognostic relevance of serum tumor markers (STM) for early and late-stage NSCLC patients treated with classical chemotherapies, novel targeted and immune therapies.
UNASSIGNED: A PubMed database search was conducted for prognostic studies on carcinoembryonic antigen (CEA), cytokeratin-19 fragment (CYFRA 21-1), neuron-specific enolase, squamous-cell carcinoma antigen, progastrin-releasing-peptide, CA125, CA 19-9 and CA 15-3 STMs in NSCLC patients published from 2008 until June 2022.
UNASSIGNED: Out of 1069 studies, 141 were identified as meeting the inclusion criteria. A considerable heterogeneity regarding design, patient number, analytical and statistical methods was observed. High pretherapeutic CYFRA 21-1 levels and insufficient decreases indicated unfavorable prognosis in many studies on NSCLC patients treated with chemo-, targeted and immunotherapies or their combinations in early and advanced stages. Similar results were seen for CEA in chemotherapy, however, high pretherapeutic levels were sometimes favorable in targeted therapies. CA125 is a promising prognostic marker in patients treated with immunotherapies. Combinations of STMs further increased the prognostic value over single markers.
UNASSIGNED: Protein STMs, especially CYFRA 21-1, have prognostic potential in early and advanced stage NSCLC. For future STM investigations, better adherence to comparable study designs, analytical methods, outcome measures and statistical evaluation standards is recommended.

BACKGROUND: Previously considered inoperable patients (borderline resectable, locally advanced, synchronous oligometastatic or metachronous pancreatic adenocarcinoma (PDAC)) are starting to become resectable thanks to advances in chemo/radiotherapy and the reduction in operative mortality.
METHODS: This narrative review presents a chosen literature selection, giving a picture of the current state of treatment of these patients.
RESULTS: Neoadjuvant therapy (NAT) is generally recognized as the treatment of choice before surgery. However, despite the increased efficacy, the best pathological response is still limited to 10.9-27.9% of patients. There are still limited data on the selection of possible NAT responders and how to diagnose non-responders early. Multidetector computed tomography has high sensitivity and low specificity in evaluating resectability after NAT, limiting the resection rate of resectable patients. Ca 19-9 and Positron emission tomography are giving promising results. The prediction of early recurrence after a radical resection of synchronous or metachronous metastatic PDAC, thus identifying patients with poor prognosis and saving them from a resection of little benefit, is still ongoing, although some promising data are available.
CONCLUSIONS: In conclusion, high-level evidence demonstrating the benefit of the surgical treatment of such patients is still lacking and should not be performed outside of high-volume centers with interdisciplinary teams of surgeons and oncologists.

Carbohydrate antigen 19-9 (CA 19-9) is a tumor marker used clinically to support the diagnosis and recurrence of pancreatic adenocarcinoma. CA 19-9 levels may be found to be elevated too in benign conditions, including hepatobiliary diseases such as choledocholithiasis, cholangitis, or cholestasis of any etiology. In this case, we are presenting a case of a 66-year-old man who has presented with diffuse abdominal pain and has been then found to have choledocholithiasis and obstructive jaundice treated with biliary sphincterotomy and balloon extraction. In the setting of extensive unclear gastroenterological surgeries, tumor markers were obtained, and the results revealed markedly elevated CA 19-9 with negative other tumor markers and a negative workup for malignancy. After reviewing the literature, we found that although CA 19-9 has been studied in diagnosing pancreatic and biliary malignancies, the serum level may also be elevated in many other benign conditions. As a result, the results must be individualized according to the clinical scenario of each patient.

Pancreatic ductal adenocarcinoma (PDAC), a highly aggressive malignancy with a poor prognosis is usually detected at the advanced stage of the disease. The only US Food and Drug Administration-approved biomarker that is available for PDAC, CA 19-9, is most useful in monitoring treatment response among PDAC patients rather than for early detection. Moreover, when CA 19-9 is solely used for diagnostic purposes, it has only a recorded sensitivity of 79% and specificity of 82% in symptomatic individuals. Therefore, there is an urgent need to identify reliable biomarkers for diagnosis (specifically for the early diagnosis), ascertain prognosis as well as to monitor treatment response and tumour recurrence of PDAC. In recent years, proteomic technologies are growing exponentially at an accelerated rate for a wide range of applications in cancer research. In this review, we discussed the current status of biomarker research for PDAC using various proteomic technologies. This review will explore the potential perspective for understanding and identifying the unique alterations in protein expressions that could prove beneficial in discovering new robust biomarkers to detect PDAC at an early stage, ascertain prognosis of patients with the disease in addition to monitoring treatment response and tumour recurrence of patients.

The role of preoperative CA 19-9 levels in patients with ovarian mature cystic teratoma (MCT) and the association of elevated levels of the biomarker with patients\' and tumor characteristics were evaluated. Four electronic databases were searched for articles published up to September 2019. Trials that evaluated the significance of elevated CA 19-9 in patients with ovarian MCTs and publications with > 20 patients were considered eligible for inclusion. Seven studies that included 995 patients with an ovarian MCT who were evaluated with elevated (n = 364) or normal (n = 631) CA 19-9 levels were included. Mean tumor size was significantly increased in patients with elevated CA 19-9 levels (p = 0.038). The rate of ovarian torsion was significantly increased in the elevated CA 19-9 group (p = 0.04). The present study highlights the importance of CA 19-9 as a marker in the diagnosis of MCT, and a meta-analysis supports that it could raise a high degree of clinical suspicion of early recognition of torsion and early surgical management due to complications related to increased size. Nonetheless, the diagnostic value of CA 19-9 is still limited and CA 19-9 can still serve only as a supplementary diagnostic tool in patients with MCTs.

Pancreatic cancer is an aggressive tumor with a dismal prognosis, biomarkers that can detect tumor in its early stages when it may be amenable to curative resection may improve prognosis. At present, serum CA 19-9 is the only validated tumor marker in widespread clinical use, but precise knowledge of its role in pancreatic cancer diagnosis, staging, determining resectability, response to chemotherapy and prognosis remains limited. A comprehensive search was performed using PubMed with keywords \"pancreatic cancer\" \"tumor markers\" \"CA 19-9\" \"diagnosis\" \"screening\" \"prognosis\" \"resectability\" and \"recurrence\". All English language articles pertaining to the role of CA 19-9 in pancreatic cancer were critically analyzed to determine its utility as a biomarker for pancreatic cancer. Serum CA 19-9 is the most extensively studied and clinically useful biomarker for pancreatic cancer. Unfortunately, CA 19-9 serum level evaluation in pancreatic cancer patients is limited by poor sensitivity, false negative results in Lewis negative phenotype (5-10%) and increased false positivity in the presence of obstructive jaundice (10-60%). Serum CA 19-9 level has no role in screening asymptomatic populations, and has a sensitivity and specificity of 79-81% and 82-90% respectively for the diagnosis of pancreatic cancer in symptomatic patients. Pre-operative CA 19-9 serum level provide useful prognostic information as patients with normal CA 19-9 serum levels (<37 U/ml) have a prolonged median survival (32-36 months) compared to patients with elevated CA 19-9 serum levels (>37 U/ml) (12-15 months). A CA 19-9 serum level of <100 U/ml implies likely resectable disease whereas levels >100 U/ml may suggest unresectablity or metastatic disease. Normalization or a decrease in post-operative CA 19-9 serum levels by ≥20-50% from baseline following surgical resection or chemotherapy is associated with prolonged survival compared to failure of CA 19-9 serum levels to normalize or an increase. Carbohydrate antigen (CA 19-9) is the most extensively studied and validated serum biomarker for the diagnosis of pancreatic cancer in symptomatic patients. The CA 19-9 serum level can provide important information with regards to prognosis, overall survival, and response to chemotherapy as well as predict post-operative recurrence. Non-specific expression in several benign and malignant diseases, false negative results in Lewis negative genotype and an increased false positive results in the presence of obstructive jaundice severely limit the universal applicability of serum CA 19-9 levels in pancreatic cancer management.