Expression of the novel human gene, UBE2Q1, in breast tumors.

The novel human gene, designated ubiquitin-conjugating enzyme E2Q family member 1 (UBE2Q1) maps to chromosome 1q21.3. The gene has an open reading frame corresponding to 422 amino acids and contains a RWD domain and an E2 ubiquitin conjugating enzyme domain. Here, we investigated the expression levels of both mRNA and protein of UBE2Q1 gene in cancerous versus normal parts of breast specimens from 26 patients. Real-time PCR data showed that the relative expression level of UBE2Q1 mRNA was significantly greater in cancers than in non-cancerous tissues of breast specimens (Mean ± SEM, 0.064 ± 0.015 for cancers and 0.026 ± 0.01 for noncancerous tissues, P < 0.05 Mann-Whitney test). A rabbit polyclonal antibody was generated against an amino acid sequence predicted from the DNA sequence of UBE2Q1 gene. This antibody was used to perform Western blotting on 21 cases in our cohort of breast specimens. Thus, 13 (61.904%) of the cases showed an increase in the UBE2Q1 immunoreactivity in their cancerous tissues as compared with the corresponding normal tissues. This result along with the real-time PCR data shows that the novel human gene, UBE2Q1, is expressed in human breast and may have implications for pathogenesis of breast cancer.

Overexpression of the novel human gene, UBE2Q2, in breast cancer.

The ubiquitin-proteasome pathway facilitates the degradation of damaged proteins and regulates growth and stress response. This pathway is activated in various cancers, including breast cancer. We have previously reported that the novel human gene, UBE2Q2, is a putative ubiquitin-conjugating enzyme that is located on chromosome 15 and is overexpressed in tumor mass and invasive epithelium in head and neck squamous-cell carcinoma. Here, real-time polymerase chain reaction was used to investigate the expression levels of UBE2Q2 gene in a collection of 21 breast cancer tissues matched with normal adjacent counterparts. Immunohistochemistry and Western blot testing were also performed on formalin-fixed, paraffin-embedded tissue sections by using a rabbit polyclonal antibody that we generated against an amino acid sequence predicted from the DNA sequence of UBE2Q2 gene. In the 21 cases investigated, a high increase in the expression of UBE2Q2 mRNA was found in 8 breast cancers (38.1%), a moderately increased UBE2Q2 expression was observed in 7 cases (33.3%), and no significant changes were detected in 6 cases (28.6%) of tumor samples when compared with corresponding normal tissues. Consistently, a higher level of immunoreactivity for UBE2Q2 protein was detected in invasive epithelium of cancerous tissues when compared with that in the normal epithelium. Our data suggest that the novel human gene UBE2Q2 may have implications for pathogenesis of breast cancer and could be used in molecular diagnosis purposes in the future.