DMBT1 is frequently downregulated in well-differentiated gastric carcinoma but more frequently upregulated across various gastric cancer types.
Well-differentiated gastric carcinomas are considered to represent a distinct entity emerging via specific molecular changes different from those found in other gastric carcinoma types. The gene deleted in malignant brain tumours 1 (DMBT1) at 10q25.3-q26.1 codes for a protein presumably involved in cell differentiation and protection and has been proposed as a candidate tumour suppressor for brain and epithelial cancer. One study reported a loss of DMBT1 expression in 12.5% (5/40) of gastric cancer samples. Here, we examined in more detail DMBT1 protein and mRNA expression in 78 primary gastric tumour samples and corresponding normal gastric mucosa. DMBT1 was expressed in all non-tumour gastric mucosa tissues. Eleven out of 71 (15%) gastric tumours were negative for the DMBT1 protein in immunohistochemical analyses. Lack of DMBT1 expression was significantly more frequently found in well-differentiated gastric tumours (6/18 well-differentiated tumours vs. 5/53 other subtypes; P=0.025). Quantitative RT-PCR revealed a downregulation of the DMBT1 mRNA for 8/21 (38%) cases, while the remaining 13 cases (62%) displayed a substantial upregulation. Our data suggest that a loss of DMBT1 expression may preferentially take place in well-differentiated gastric carcinoma. However, an upregulation of DMBT1 expression is more frequently found across all gastric cancer types.
Conde
Ana R
AR
Faculdade de Farmacia da Universidade de Lisboa, 1649-003 Lisboa, Portugal. arconde@ff.ul.pt
Martins
Ana P
AP
Brito
Miguel
M
Manuel
Armandina
A
Ramos
Sância
S
Malta-Vacas
Joana
J
Renner
Marcus
M
Poustka
Annemarie
A
Mollenhauer
Jan
J
Monteiro
Carolino
C
D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D015536:Down-Regulation; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis; D011956:Receptors, Cell Surface / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology*; D025521:Tumor Suppressor Proteins
D014408:Biomarkers, Tumor; D002135:Calcium-Binding Proteins; C108174:DMBT1 protein, human; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D025521:Tumor Suppressor Proteins