Detection of nonmelanoma skin cancer micrometastases in lymph nodes by using reverse transcriptase-polymerase chain reaction for keratin 19 mRNA.
BACKGROUND
A new sensitive method for the detection of skin cancer micrometastases in lymph nodes is based on amplification of keratin 19 (K19) mRNA by reverse transcriptase-polymerase chain reaction (RT-PCR).


OBJECTIVE
To compare results of RT-PCR with those of histological examination in terms of the detection rate of skin cancer micrometastases.


METHODS
Twenty-six lymph nodes obtained from 13 patients with squamous cell carcinoma (SCC), eccrine porocarcinoma and Paget's disease were investigated by histological examination (haematoxylin and eosin sections) and RT-PCR. RT-PCR was performed on extracted RNA by using K19 primer pairs. RT-PCR products were visualized by ethidium bromide staining and confirmed by non-radioactive hybridization with K19-specific probes.


RESULTS
All of 10 histologically positive lymph nodes yielded the expected 460-bp band. Of the 16 histologically negative lymph nodes, one (6%) was found by RT-PCR to express K19 mRNA, indicating the presence of micrometastases which could not be detected by histological examination. A serial dilution study using RNA extracted from SCC cells mixed with RNA extracted from normal lymph node cells showed a detection sensitivity of K19 RT-PCR of 10-5 micro g cancer cell RNA in 1 micro g lymph node RNA. Nested RT-PCR showed a detection sensitivity of one tumour cell in 106 lymphocytes.


CONCLUSIONS
These results demonstrate the usefulness of K19 RT-PCR for the detection of skin cancer micrometastases in lymph nodes.
Kamiya
M
M
Department of Dermatology, Gifu University School of Medicine, Tsukasamachi 40, Gifu 500-8705, Japan.
Ichiki
Y
Y
Kamiya
H
H
Yamamoto
A
A
Kitajima
Y
Y
D014408:Biomarkers, Tumor / Q000235:genetics*; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary*; D006801:Humans; D007633:Keratins / Q000235:genetics*; D008207:Lymphatic Metastasis; D009363:Neoplasm Proteins / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms
D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D007633:Keratins