Gd. Pinczower et al., MONOCLONAL-ANTIBODY 4D3 DETECTS SMALL-INTESTINAL MUCIN ANTIGEN (SIMA)GLYCOPROTEIN IN THE SERUM OF PATIENTS WITH COLORECTAL-CANCER, International journal of cancer, 54(3), 1993, pp. 391-396
We have developed a sensitive ELISA using MAb 4D3 for the detection of
a novel epitope on Small Intestinal Mucin Antigen (SIMA) and report h
ere that SIMA is present in the serum of patients with colorectal canc
er. SIMA has been shown to occur in tissue from a high proportion of p
atients with colorectal cancer. SIMA derived from serum was similar to
tissue-derived SIMA: both eluted in the void volume of a Superose 6 c
olumn indicating a molecular weight above 5,000 kDa and they exhibited
similar buoyant densities on CsCl gradients. The ELISA was most relia
ble after pre-treatment of serum with 0.4 M perchloric acid to remove
interfering substances. The upper limit for SIMA in normal serum was s
et as the mean plus 2 standard deviations determined from a group of 9
7 healthy control subjects. In a sample of 113 patients with colorecta
l cancer, SIMA serum levels were elevated in 15% of patients with Duke
s' Stage A, 38% with Stage B, 32% with Stage C and 75% with Stage D co
lorectal cancer. SIMA serum levels were compared with those of the wid
ely used tumor marker, carcino-embryonic antigen (CEA). The SIMA assay
detected a significant number of sera that were not detected by the t
est for CEA. We propose that SIMA will prove to be a valuable serologi
cal tumor marker, in combination with CEA and other tumor markers, for
the detection of colorectal cancer.