In pleural effusions, where PAPP‐A is close to 50‐fold elevated as compared to serum, the degradation of IGFBP‐2 remains similar to that in serum 49 and in serum from lung cancer patients the major part of IGFBP‐2 circulates in its free form (data in preparation). This evidence concerns the gene IGFBP2 and lung cancer.