Background and objective Formalin-fixed and paraffin-embedded tissue (FPE) with long term follow-up and clinicopathological data are extensively available and easily accessible. They represent an extensive source of genetic materials and proteins to be investigated for clinical usage. We conducted the study to explore the possibility of extracting RNA from FPE of lung cancer, and checking up the transcription levels of the promyelocytic leukemia gene (PML) by RT-PCR. Methods five fresh frozen lung adenocarcinoma tissues and 40 FPEs of lung cancer were chosen; FPEs had been conserved for 60-85 months. All samples had been identified lacking expression of PML protein by immunohistochemical staining. The total RNA was extracted by using Trizol one-step method, and verified by testing OD value. RT-PCR was used to detect the transcription level of PML gene. Results The RNAs from both tissues had the OD value ranging from 1.7 to 2.1. RT-PCR results displayed that mRNA of PML (295 bps) and β-actin (318 bps) was not absent in all cancer tissues. Conclusion Trizol one-step method is easily accessible, and reliable for extracting RNA in fragments around 300 bases from FPEs. Loss of PML protein in lung cancer is not caused by downward adjustment of mRNA.