Table 1.

Typical tumor markers during treatment.

Tumor marker	After surgery	Before erlotinib	After transformation to SCLC
CEA <3 µg/L	0.55	2.12	12.55
NSE <12 µg/L	2.73	5.44	4.65
ProGRP <45 pg/mL	18	33.68	5.90

CEA, carcinoembryonic antigen; NSE, neuron-specific enolase; ProGRP, progastrin-releasing peptide.