Abstract: Objective To explore the clinical characteristics of small cell lung cancer（SCLC）patients with negative pro-gastrin-releasing peptide precursor（ProGRP）. Methods The clinical data of hospitalized patients with SCLC between December 2016 and May 2021 were retrospectively analyzed. There were 25 negative ProGRP patients and 75 positive ProGRP patients. The clinicopathological characteristics and survival differences between the two groups were compared,and changes in ProGRP levels were observed during monitoring the effects in ProGRP-negative SCLC patients. Results ProGRP-negative SCLC patients accounted for 25%. ProGRP-negative SCLC patients and ProGRP-positive SCLC patients had no significant differences in gender, age, smoking history, clinical stage, and NSE positive rate. Of which, 92% were in extensive stage disease（ED）, and the positive reate of NSE was 84%. The progression-free survival（PFS）of ProGRP-negative SCLC patients was significantly lower than that of the ProGRP-positive patients. For ProGRP-negative SCLC patients,the serum level of ProGRP maintained at a relatively low level in different periods of efficacy monitoring of tumor therapy,even disease progression. Conclusions ProGRP-negative SCLC patients have a poor prognosis. It may be a special type of SCLC.

Key words: Small cell lung cancer, Gastrin releasing peptide precursor, Clinical characteristics, Neuron specific enolase