Disease relevance of SCGB2A2

• In the present study, we examined the expression of the mammaglobin genes, MGB1 and MGB2, in the sentinel lymph nodes (SLNs) of patients with breast cancer and compared our results with the histologic status of the same SLNs [1].
• Compared with immunohistochemical staining for cytokeratin 8, which detected metastases in 17 of 42 patients, reverse transcription-polymerase chain reaction (RT-PCR) for MGB1 or MGB2 genes was positive in 22 patients [1].
• We suggest that the SCGB2A2 promoter/enhancer should be particularly advantageous for gene therapy protocols involving oncolytic viruses or toxic gene transfer via adenovectors to mammary tumors [2].
• This increased sensitivity was achieved without compromising specificity, as the MGB1 transcript was not detected in 38 blood samples of healthy donors and in only 1 of 18 blood samples of patients presenting with hematologic malignancies [3].
• Human lipophilin C (77 residues; mass, 8854.1; pI, 4.94) was homologous to the rat prostatein C3 component and to human mammaglobin, a protein overexpressed in some mammary carcinomas [4].

High impact information on SCGB2A2

• Mammaglobin remains a useful marker for the detection of breast cancer cells in peripheral blood [5].
• Combination of cytology, fluorescence in situ hybridization for aneuploidy, and reverse-transcriptase polymerase chain reaction for human mammaglobin/mammaglobin B expression improves diagnosis of malignant effusions [6].
• Mammaglobin is associated with low-grade, steroid receptor-positive breast tumors from postmenopausal patients, and has independent prognostic value for relapse-free survival time [7].
• The association of mammaglobin expression with the rate of relapse was particularly favorable in patients who received adjuvant tamoxifen treatment (HR, 0.35; 95% CI, 0.17 to 0.71; P =.004) [7].
• SBEM mRNA expression was detected in >90% of invasive ductal carcinomas and correlated with the expression of a previously characterized breast-specific gene, mammaglobin-1 (n = 54; Spearman r = 0.34, P = 0.011) [8].

Chemical compound and disease context of SCGB2A2

• SCGB2A2 has previously been found overexpressed in breast tumors but possible associations between its expression and established prognostic tumor characteristics such as the levels of estrogen and progesterone receptors have not yet been investigated [9].

Biological context of SCGB2A2

• A series of vectors with deletions in the 25-kb fragment was constructed to identify important regulatory regions of the SCGB2A2 promoter [2].
• We evaluated SCGB2A2 expression at the mRNA and at the protein level by reverse-transcription polymerase chain reaction and immunocytochemistry in 52 and 32 breast tumors, respectively [9].
• The human mammaglobin gene is localized by fluorescent in situ hybridization to chromosome 11 band q13, a genomic region frequently amplified in breast neoplasia [10].
• CONCLUSIONS: MAM gene expression on leukapheresis products of high-risk breast cancer patients is an indicator of poor prognosis [11].
• This is consistent with the two predicted N-linked glycosylation sites in the primary sequence of mammaglobin and each site having an attached sugar of approximately 3500 Da [12].

Anatomical context of SCGB2A2

• As estrogen and antiestrogen treatment of estrogen-positive breast cancer cell lines does not modify SCGB2A2 expression we suggest that SCGB2A2 may be a new independent breast cancer prognostic marker [9].
• Expression of the mammaglobin gene is restricted to the adult mammary gland [13].
• Mammaglobin B (MGB2) is highly homologous to mammaglobin (MGB1), a previously characterized human gene whose expression is limited to the mammary epithelium and frequently up-regulated in human breast cancer cells [14].
• Using a nested reverse transcription-PCR assay, mammaglobin mRNA was also detected in 9 of 15 products (60%) used for autologous stem cell transplant [15].
• CONCLUSIONS: These results suggest that molecular characterization of circulating epithelial cells using mammaglobin and B305D-C offers potential for early detection of invasive breast cancer [16].

Associations of SCGB2A2 with chemical compounds

• SCGB 2A1 is homologous to mammaglobin (mammaglobin A) and the C3 component of prostatein, the major secretory protein of the rat ventral prostate [17].
• The mammaglobin gene encodes a novel, breast cancer-associated glycoprotein [15].
• Real-time reverse transcription-PCR was used to quantitate the expression levels of the highly breast-specific genes, mammaglobin, gamma-aminobutyric acid type A receptor pi subunit (GABA A(pi)), B305D-C, and B726P in the epithelial cell-enriched samples [16].
• Genes reported to be expressed during the implantation window and implicated in progesterone action, i.e. secretoglobin family 2A, member 2 (mammaglobin) and homeobox-containing proteins, were up-regulated in uncultured LATE-P-phase endometrium compared to M-phase endometrium [18].

Physical interactions of SCGB2A2

• Purification and characterization of the mammaglobin/lipophilin B complex, a promising diagnostic marker for breast cancer [12].

Regulatory relationships of SCGB2A2

• Mammaglobin was induced in cell lines significantly by GM-CSF and in clinical samples additionally by several more cytokines [19].

Other interactions of SCGB2A2

• Both SCGB2A2 mRNA and protein expression were significantly higher in estrogen-receptor-positive compared to estrogen-receptor-negative tumors (Mann- Whitney rank sum test, p = 0.04; chi-square test, p = 0.01; respectively) [9].
• In contrast, SCGB2A2 expression did not correlate with progesterone receptor levels or Nottingham grade [9].
• The protein encoded by this cDNA, which we have named mammaglobin, is homologous to a family of secreted proteins that includes rat prostatic steroid-binding protein subunit C3, human Clara cell 10-kilodalton protein, and rabbit uteroglobin [13].
• Reducing agents release lipophilin B from mammaglobin, and the free peptides are seen at their predicted molecular masses in the deglycosylated complex [12].
• All specimens were immunostained with anti-CK7, CK20, CRxA-01, and mammaglobin antibodies [20].

Analytical, diagnostic and therapeutic context of SCGB2A2

• The increased detection rate relative to histologic examination suggests that using RT-PCR for the mammaglobin genes might identify patients at higher risk compared with patients with negative RT-PCR results [1].
• Mammaglobin expression in leukapheresis products is a predictive marker of poor prognosis in women with high-risk breast cancer [11].
• RNA in situ hybridization and immunohistochemistry confirmed expression of mammaglobin A on a cellular level in endometrial and cervical cancer and their corresponding normal tissues [21].
• CONCLUSION: Our results indicate that mammaglobin, as measured by the ELISA, holds significant promise for breast cancer screening with the realistic potential to impact management of this disease [22].
• A diagnostic test that classified patients as positive for invasive breast cancer when either mammaglobin levels were >46.3 units or B305D-C levels were >11.6 units increased the sensitivity and specificity to 70.5% and 81.0%, respectively [16].

References