Colorectal cancer - CEA

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1 Colorectal cancer - CEA What is carcinoembryonic antigen? Human carcinoembryonic antigen (CEA) (MW = g/mol) is a glycoprotein involved in cell adhesion. It is normally produced during fetal development, but the production of CEA stops before birth. Therefore, it is not usually present in the blood of healthy adults, although levels are raised in heavy smokers. Both benign and malignant (harmless and cancerous) conditions can increase the CEA level in blood. The most frequent cancer which causes an increased CEA concentration is cancer of the colon and rectum (ColoRectal Cancer, CRC). The normal range for CEA concentration in an adult non-smoker is < 2.5 ng/ml and for a smoker < 5.0 ng/ml in blood. CEA ColoRectal Cancer (ng/ml) > 10 High risk 2.5 (5.0) -10 Low risk < 2.5 (5.0) Normal (Smoker) CEA assay kit For IMR on CEA, antibodies (MF-AT-CEA, MagQu) against CEA are bound to magnetic particles (MF-DEX-0060, MagQu) to obtain CEA reagent, modeled with MF-CEA The mean diameter of magnetic particles is nm. The concentration of MF-CEA-0060 is 5 mg-fe/ml. The buffer solution is PBS solution. The kit is only for research use. For each set, there are four tubes consisting: 1.0 ml MF-CEA-0060 (x 1 tube) 1.0 ml calibrator (x 2 tubes) 1.0 ml standard CEA solution (x 1 tube)

2 Standard curve By using XacPro-E, the IMR signal, IMR (%), as a function of CEA concentration φ CEA is explored and is found to follow the logistic function A B IMR(%) = φcea 1+ ( ) φ o γ + B, where A, B, φ o, and γ are fitting parameters. For example, A = 1.05, B = 3.22, φ o = 14.1, and γ = The R 2 is The error bar of each data point is resulted from the multiple detections of IMR signal for the CEA concentration IMR (%) φ CEA (ng/ml) Low-detection limit The low-detection limit is usually defined as the concentration showing the IMR signal higher than the noise level by triple standard deviation for IMR signals at low concentrations, i.e. 3-σ criterion. The standard deviation for IMR at low concentrations, such as 0.1-ng/ml CEA, was found to be %. Thus, the low-detection-limit IMR signal is ( x0.014) % = %. Via the logistic function, the low-detection limit for assaying CEA using IMR is 0.21 ng/ml. Linearity and dynamic range With the logistic function, the detected IMR signals are converted to CEA concentrations, denoted with φ CEA-IMR. The relationship between φ CEA-IMR and φ CEA is plotted. 1

3 φ CEA-IMR (ng/ml) ng/ml Slope = 1.21 R 2 = ng/ml Slope = 0.97 R 2 = φ CEA (ng/ml) φ CEA-IMR is proportional to φ CEA with a slope of 1.21 for the φ CEA from 0.2 ng/ml to 1000 ng/ml, as denoted with the dashed line. According to 510k guideline, the acceptable slope is within the range from 0.9 to 1.1. Thus, 1000 ng/ml of φ CEA is beyond the dynamic range for assaying CEA because the corresponding slope is higher than 1.1. The slope of the φ CEA-IMR -φ CEA curve (solid line) for the φ CEA from 0.2 ng/ml to 500 ng/ml is then calculated and found as 0.97, which is within the range from 0.9 to 1.1. Hence, the dynamic range of assaying CEA using IMR is from 0.21 ng/ml to 500 ng/ml. In case, the coefficient of determination R 2 for the φ CEA-IMR -φ CEA curve is Interference test CEA is frequenctly assayed in blood, which might also contain hemoglobin, bilirubin, intrafat, vascular endothelial growth factor (VEGF) due to patients with hemolysis, jandice, or hyperlipoidemia. The interfernece from hemoglobin (Hb), cojugated bilirubin (C-BL), and triglyceride (TG) to IMR on CEA is investigated. In addition, other bio-materials naturally existing in serum, such as uric acid, rheumatoid factor, intra lipid, albumin etc., are interfering materials. Other interfering materials might include drugs or chemicals because of taking medicine for treating inflammatory diseases, virus and Sample Mean value p Interfering material Concentration No. of IMR(%) value 1 None ± Hemoglobin µg/ml 1.71 ±

4 3 Bilirubin 600 µg/ml 1.66 ± Triglyceride µg/ml 1.72 ± Uric acid 200 µg/ml 1.69 ± Rheumatoid factor 500 IU/ml 1.68 ± Intra lipid µg/ml 1.67 ± Albumin µg/ml 1.67 ± Acetaminophen 300 µg/ml 1.72 ± Acetyl cysteine 150 µg/ml 1.68 ± Acetylsalicylic acid 500 µg/ml 1.74 ± Ascorbic acid 300 µg/ml 1.71 ± Atrovastatin 3 µg/ml 1.71 ± Furosemide 4000 µg/ml 1.70 ± Ibuprofen 1000 µg/ml 1.72 ± Levodopa 20 µg/ml 1.71 ± Methyldopa 200 µg/ml 1.72 ± Naprosyn sodium 500 µg/ml 1.66 ± Phenylbutazone 400 µg/ml 1.65 ± Prednisone 5 µg/ml 1.69 ± Tegafur with uracil 50 µg/ml 1.70 ± Theophylline 50 µg/ml 1.69 ± Warfarin 50 µg/ml 1.66 ± Ampicillin sodium 1000 µg/ml 1.67 ± Cefoxitin 2500 µg/ml 1.73 ± Cyclosporeine A 10 µg/ml 1.71 ± Doxycycline hyclate 50 µg/ml 1.68 ± Irinotecan 100 µg/ml 1.69 ± Lovastatin 2.5 µg/ml 1.72 ± Metronidazole 200 µg/ml 1.70 ± Oxaliplatin 100 µg/ml 1.72 ± Rifampicin 60 µg/ml 1.74 ± bacteria infection, cancers, cardiovascular disease, etc. All the natural bio-materials and drugs or chemicals are spiked into serum, which has 5 ng/ml CEA. The concentrations of these interfering materials are also listed. Worth noting, the concentrations of interfering materials are much higher than popular levels. 3

5 The IMR signal of the serum (Sample No. 1) with only 5-ng/ml CEA is used as a reference. All other IMR signals of serum samples (Sample Nos. 2-32) with both 5-ng/ml CEA and interfering materials are compared with the referenced IMR signal. The corresponding p values are calculated via T-Test and are shown in Table 1. The p values of IMR signals for serum samples with interfering materials with respect to that of pure CEA-serum sample are higher than 0.05, as shown in Table 1. This implies that the assay for CEA in serum is not interfered with bio-molecules, drugs and chemicals listed in Table 1 except acetyl cysteine and furosemide. CEA assay for CRC patients Thirty serum samples from patients with colorectal cancer (CRC) confirmed with pathological evidence are used for CEA assay via IMR with CEA reagent. The results are shown with cross symbols ( ). It was found that the CEA concentrations φ CEA-IMR for these patients ranged from 6.0 to 20.0 ng/ml. As the CEA concentrations in the serum samples of twenty-four normal people were detected via IMR, it was found that the CEA concentrations were from 0.6 to 1.5 ng/ml, as shown with dots ( ) Normal control CRC Portion (%) φ CEA-IMR (ng/ml) Through receiver operating characteristic (ROC) curve analysis, the threshold for diagnosing CRC by assaying on CEA in serum using IMR method was found to be 4.05 ng/ml, which resulted in the clinic sensitivity and specificity to be 0.90 and 0.87, respectively. 4

6 Sensitivity specificity Stability The stability tests are done by measuring the time dependent mean value of particle diameter, as well as the IMR signal for 5-ng/ml CEA solution. The particle diameter is measured by using dynamic laser scattering. The IMR signal is detected by using XacPro-E. It was found that, as storing MF-CEA-0060 at 2 8 o C, the mean diameter and the IMR signal remain unchanged for 12 months. Mean diameter (nm) Stored at 2-8 o C Storing period of time (months) 2.00 IMR (%) φ CEA =5 ng/ml Storing period of time (months) Storage Please store MF-CEA-0060 at 2 8 o C and far away from magnets. Reference(s) 5

7 K.W. Huang, S.Y. Yang, H.E. Horng, J.J. Chieh, H.H. Chen, C.C. Wu, J.H. Chen, I.T. Lin, C.C. Yang, H.H. Chen, and H.C. Yang, Time-evolution contrast of target MRI using high-stability antibody functionalized magnetic nanoparticles: An animal model, J. Nanomater. (accepted). A system for diagnosing colorectal cancer, Taiwan patent, S.Y. Yang, J.F. Chang, T.C. Chen, C.C. Yang, and C.S. Ho, Study of the temperature dependent immuno-reaction kinetics for the bio-functionalized magnetic nanoparticle assay of bio-markers of colorectal cancer, Appl. Phys. Lett. 104, (2014). 6