Due to an error, the same abstract was used for the ISOBM poster section as well as the oral section (workshop 5). Below are the 2 abstracts. Comments on the congress advances will follow in the incoming days.

Poster presentation:

A New RECAF ELISA and its Correlation with the Chemiluminescence RECAF Assay

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Irene Ng^**, Janneta Tcherkassova^**, Nina Lyubimova^***, Ricardo Moro^* (rmoro@biocurex.com)

^*BioCurex, 215-7080 River Road, Richmond, BC, Canada V6X 1X5

^**Pacific Biosciences Research Centre, Richmond BC, Canada

^***N.N. Blokhin Cancer Research Centre, Moscow, Russia

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Aims: To develop an alpha fetoprotein receptor (RECAF) ELISA for the early detection of cancer, analogous to the previously presented RECAF radioimmunoassay (RIA) and chemiluminescence (CIA) tests. ELISAs do not use radioactivity and colorimetric plate readers are ubiquitous in clinical and research laboratories.

Methods: We coated Nunc Maxisorp plates with anti-RECAF IgM mAb 1.4G11. Horseradish peroxidase labeled RECAF was mixed with the serum sample and incubated in the plate wells for 3 hours followed by washing and developing with 3,3’,5,5’-tetramethylben... (TMB) substrate. The reaction was stopped with HCl and the plates were read in an ELISA plate reader using a 450nm filter.

Results: Studies showed discrimination between bladder, kidney, stomach, and other types of cancer (n = 77) and normal samples (n = 93). At 95% specificity, there was 90% sensitivity on the ELISA and 95% sensitivity on the CIA. The ratios between average cancer and normal readings are 2.7 for the ELISA (cancer average = 6,964 RECAF Units, normal average = 2,533 RECAF Units) as compared to 2.5 for CIA (cancer average = 7,062 RECAF Units, normal average = 2,815 RECAF Units). The regression coefficient (r) between ELISA and CIA Units determinations was 0.92. At a cutoff = 4,500 Units for both assays, the diagnosis correspondence was 0.978.

Conclusions: We have developed a RECAF ELISA that differentiates between multiple types of cancer and normal sera that is closely correlated to the performance of the CIA. The broad availability of ELISA readers should expand the use of this promising cancer marker.

Workshop 5, Oral presentation:

RECAF as a Cancer Marker for Gastrointestinal Diseases

Dr. Ricardo Moro,

BioCurex Inc., Vancouver, Canada (www.biocurex.com)

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Aim: To characterize the performance of a serum test based on the RECAF cancer marker for detection of cancers of the gastrointestinal tract.

Method: Competitive RIA, ELISA and chemiluminescence assays were developed to measure the concentration of the RECAF cancer marker in the serum of cancer patients and healthy individuals. The assay was performed on 96 well plates coated with an anti-RECAF monoclonal antibody. A suitable dilution of the serum was mixed with labeled pure RECAF using ¹²⁵I, horseradish peroxidase or acridinium respectively. After incubating for 2 hours and thorough washing, the remaining labeled RECAF was measured with either a gamma counter, an ELISA reader with a 450 nm filter (after the addition of TMB to develop the reaction) or a flash plate luminometer. ROC Statistical analysis was used to determine the test’s ability to discriminate cancer samples from normal samples.

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Results: All formats performed in a similar manner (r>0.85). The table below shows the results:

*=Chemiluminescence, #=RIA, &=ELISA.

RECAF differentiated colorectal cancers from normal samples better than CEA and CA19.9.

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Conclusion: The RECAF blood tests discriminate cancer samples from samples from healthy individuals with high sensitivity and specificity and therefore it could be used as one of the clinical laboratory tests to identify these diseases.