Just as Holdenrieder et al demonstrated that high levels of proGRP before the first cycle of treatment, as well as the insufficient decline in proGRP level before the second cycle of treatment were related to the poor outcome of SCLC patients; and proGRP level before the second cycle of chemotherapy was the early estimation of therapy response, reaching the AUC of 71.3% in ROC curve. Here, GRP is linked to small cell lung carcinoma.