Combination of serum CST4 and DR-70 contributes to early diagnosis of colorectal cancer.

Background: Early diagnosis is of great significance for the prognosis of colorectal cancer (CRC) patients. Either serum cystatin S (CST4) or DR-70 has been demonstrated to play an important role on the diagnosis for CRC, however, the diagnostic performances of individual and combined detection of serum CST4 and DR-70 for the patients with CRC at early stage have still not been clarified up to now.

Methods: The performances of CST4 and DR-70 were evaluated by ELISA for the early diagnosis of CRC with 288 retrospective serum samples. A training set comprised of 64 patients with early CRC, 64 patients with colorectal benign lesions (CBL), and 64 healthy controls (HC) was used to develop the predictive model for early CRC. And then, data obtained from an independent validation set was applied to evaluate and validate the predictive model.

Results: In the training set, the levels of CST4 and DR-70 in early CRC group were significantly higher than that in CBL group/HC group (P < 0.001); serum CST4 presented the AUC of 0.927 for early CRC patients, with 57.8% sensitivity at 95.3% specificity; serum DR-70 presented the AUC of 0.725 for early CRC patients, with 29.7% sensitivity at 95.3% specificity; combination of serum CST4 and DR-70 presented the AUC of 0.941, with 68.8% sensitivity at 93.8% specificity. Additionally, the combination of serum CST4 and DR-70 showed the AUC of 0.940 for early CRC patients, with 71.9 % sensitivity at 89.1% specificity in the validation set.

Conclusions: Both serum CST4 and DR-70 present the diagnostic value for the patients with early CRC, and the combination of CST4 and DR-70 contributes to the further improvement of the early diagnosis for CRC.