Overexpression of Fos-related antigen-1 in head and neck squamous cell carcinoma.
The activating protein-1 (AP-1) family of transcription factors has been implicated in the control of proliferation and differentiation of keratinocytes, but its role in malignant transformation is not clear. The aim of this study is to assess the pattern of mRNA expression of jun-fos AP-1 family members in 45 samples of head and neck squamous cell carcinomas (HNSCC) and matched adjacent mucosa by means of Northern blot analysis. Transcripts of all family members were identified, except for JunB that was detected only by means of reverse transcription polymerase chain reaction. Neither c-Fos nor JunD or FosB mRNA differed between tumours and normal tissues. We observed a strong Fos-related antigen-1 (Fra-1) and Fra-2 expression, but only Fra-1 mRNA densitometric values were higher in tumour, compared to normal adjacent mucosa (t-test, P = 0.006). A direct relationship between the positive expression of Fra-1 mRNA, above tumour median, was associated with the presence of compromised lymph nodes (Fischer exact test, P = 0.006). In addition, Fra-1 protein staining was assessed in a collection of 180 tumours and 29 histologically normal samples adjacent to tumours in a tissue array. Weak reactivity, restricted to the basal cell layer, was detected in 79% of tumour adjacent normal tissues, opposed to the intense reactivity of cancer tissues. In the subgroup of oral cancers, we have observed a shift in Fra-1 immunoreactivity, as long as the number of patients in each category, cytoplasmic or nuclear/cytoplasmic staining, was analysed (Fischer exact test, P = 0.0005). Thus, Fra-1 gene induction and accumulation of Fra-1 protein may contribute to the neoplastic phenotype in HNSCC.
Mangone
Flavia R R
FR
Faculdade de Medicina da Universidade de São Paulo, Departamento de Radiologia, Disciplina de Oncologia, 01246-903 São Paulo, Brazil.
Brentani
M Mitzi
MM
Nonogaki
Suely
S
Begnami
Maria Dirlei F S
MD
Campos
Antonio Hugo J F M
AH
Walder
Fernando
F
Carvalho
Marcos B
MB
Soares
Fernando A
FA
Torloni
Humberto
H
Kowalski
Luiz P
LP
Federico
Miriam H H
MH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015152:Blotting, Northern / Q000379:methods; D002294:Carcinoma, Squamous Cell / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics; D005260:Female; D051921:Fos-Related Antigen-2; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D006258:Head and Neck Neoplasms / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics*; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D012334:RNA, Neoplasm / Q000032:analysis; D018808:Transcription Factor AP-1 / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics; D015533:Transcriptional Activation; D000099169:Fos-Related Antigen 1
D004268:DNA-Binding Proteins; D051921:Fos-Related Antigen-2; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D000099169:Fos-Related Antigen 1; C497872:FOSL2 protein, human