SPOPL is a 392 amino acid nuclear protein that may be involved in ubiquitination and proteasomal degradation processes. Belonging to the Tdpoz family, SPOPL contains one BTB (POZ) domain and one MATH domain. SPOPL forms a complex with a member of the cullin family. The gene that encodes SPOPL includes 71,768 bases, four transcripts and maps to the human chromosome 2q22.1. Chromosomal arm 2q22-23 has been identified as one of fifteen hot spots thought to be involved in head and neck squamous cell carcinoma (HNSCC). Chromosome 2, which consists of 237 million bases, encodes over 1,400 genes and makes up approximately 8% of the human genome. A number of genetic diseases are linked to genes on chromosome 2 including Harlequin icthyosis, sitosterolemia and Alstr鰉 syndrome.