During the amplification of a 202 base pair (bp) fragment around the 61 st codon of the N-ras gene, an extra band of about 150 bp in length was observed when genomic DNA from a human epidermoid carcinoma cell line was used as template. This fragment was cloned and sequenced. However, this sequence was not found in the databank. RT-PCR experiments indicated that the sequence is expressed in the cells about 8 h after serum induction. The relevant RNA hybridized to one strand of the sequence but not to the other.