The Department of Laboratory Medicine of Cancer Hospital of Fudan University is able to detect small cell lung cancer more accurately through a tumor marker test called gastrin-releasing peptide precursor (ProGRP). This means that lung cancer can be classified and staged in a relatively short period of time by just “drawing some blood”, which can help guide the formulation of subsequent treatment plans. It is reported that small cell lung cancer accounts for about 20% of all lung cancer patients. Professor Chen Haiquan, the chief expert of the multidisciplinary comprehensive diagnosis and treatment team of Fudan University Cancer Hospital, pointed out that the treatment of lung cancer tends to be individualized and precise, and the classification and staging of lung cancer is very important for the selection of treatment methods. The work of classification and staging relies not only on pathological “gold standard” but also on important auxiliary means such as blood tumor markers. In clinical work, some patients cannot receive pathological biopsy due to the deep location of the tumor and other diseases. This often makes it difficult to develop subsequent clinical protocols. After a series of clinical studies and basic experiments, this tumor marker, ProGRP, has been shown to be more sensitive in the detection of small cell lung cancer. In a specific expression profile of the ProGRP marker in nine different tumors, it showed the highest positive rate of 66% in small cell lung cancer, while the other eight tumors (e.g., breast cancer and pancreatic cancer) showed a positive rate of less than 10%. Follow-up studies also confirmed that ProGRP markers were up to 72 percent sensitive and about 95 percent specific in the differential diagnosis of small cell lung cancer and non-small cell lung cancer. “We can see that ProGRP is more sensitive than traditional NSE markers in identifying small cell lung cancer, while being equally useful for the differential diagnosis of benign diseases such as small lung nodules.” Professor Guo Lin, director of the Department of Laboratory Medicine, emphasized. In addition to determining the type of lung cancer, ProGRP can also assess the efficacy and predict recurrence. Professor Lu Renquan of the Department of Laboratory Medicine strongly recommends that patients with small cell lung cancer need to be tested for the new tumor marker ProGRP during follow-up, and if this marker is found to be significantly elevated (more than 25%), it should be retested once within 1 month, and if it is still elevated, it indicates possible recurrence or the presence of metastasis, and patients need to undergo other tests such as imaging results for further confirmation. “From the current experimental data, ProGRP is an independent prognostic factor for small cell lung cancer and a more sensitive tumor marker for monitoring tumor recurrence and metastasis, with a sensitivity of 74%, and lung cancer patients in the follow-up period need to pay full attention to this index.” Currently, ProGRP index is also used in the clinic to assess the effect of treatment. According to Prof. Chen Haiquan of the Department of Thoracic Surgery, if treatment is effective, the level of ProGRP value will drop significantly, and if treatment is ineffective the indicator will not drop or even rise further. This has also become an important reference indicator for clinicians to develop protocols and assess the efficacy of treatment, which has strong clinical guidance significance.