Gene expression signatures that classify the mode of invasion of primary oral squamous cell carcinomas

Abstract

To identify molecular signatures and establish a new diagnostic model for progressive oral squamous cell carcinoma (OSCC). Total RNAs were isolated from primary OSCCs from both node-positive and -negative patients and used in cDNA microarray analysis. To identify marker genes representing a malignant phenotype, their expression was further examined by quantitative reverse transcription-PCR (QRT-PCR) in 64 OSCC tissues. Using Fisher's linear discriminant analysis (LDA) fitted with a stepwise increment method, we created discriminatory predictor models. The stability of these models was examined using leave-one-out cross validation. Immunohistochemical analysis was performed. Among the 16,600 possible target cDNAs in the array analysis, 83 genes demonstrated significantly differential signals (>2-fold). We further identified 53 marker genes that can be implicated in the Yamamoto-Kohama's (YKs) mode of invasion for OSCCs (P < 0.06). Using LDA fitted with a stepwise increment method, we created four discriminatory predictor models based on 16- to 25-gene signatures which could best distinguish the five established grades of YKs mode of invasion. Leave-one out validation demonstrated that the stability of these models was 92-95%. For validation, we also examined an independent set of 13 primary OSCCs; the predictor models determined the invasion status from 77% to 100% (on average, 85%) fidelity with the pathological observations. TGM3 protein expression was markedly suppressed in highly invasive OSCCs. We reveal novel gene expression alterations during the progression of OSCC, and have constructed prediction models for the evaluation of the invasion status of these cancers.

Loss of ELF3 immunoexpression is useful for detecting oral squamous cell carcinoma but not for distinguishing between grades of epithelial dysplasia

“…Our CLSP immunostaining results are in agreement with previously reported down-regulation of CLSP in advanced OSCC [12] and under-expression of CLSP in cervical cancer [40,41] but contrast with over-expression of CLSP in invasive and metastatic breast cancer [42]. A direct role for CLSP in carcinogenesis is countered by reports that transient transfection of CLSP into immortalized human keratinocytes and cervical cancer cell lines did not influence cell phenotype [40].…”

“…Expression of CLSP is up-regulated in oral leukoplakia [8] and PMOLs [6], but down-regulated in advanced OSCC [12]. ELF3 is a member of ETS (E26 transformation-specific) family of transcription factors which is induced during keratinocyte differentiation in normal epithelia [13] and has been shown to be down-regulated in PMOLs [8,9].…”

Gene expression analyses associated with malignant phenotypes of metastatic sub-clones derived from a mouse oral squamous cell carcinoma Sq-1979 cell line

“…Next, comprehensive gene expression was compared between Sq-1979 and L cells to identify differentially expressed mRNAs. Our previous studies demonstrated that the expression of certain mRNAs, such as keratin1 and transglutaminase 3, exhibit continual changes from pre-cancerous to cancerous tissues and to further malignant OSCCs (4,9). In the present study, it was revealed that the expression of certain marker mRNAs could be an index for evaluating the histological grading of precancerous and OSCC tissues obtained from patients.…”

“…cDNA samples from 18 patients with OSCC (median age, 65 years; 7 male, 11 female; age range, 38-91 years) and 18 patients with LP (median age, 72 years; age range, 57-98 years) were incorporated into the present study. Tissue samples that had been surgically resected in the Dental Hospital of Hokkaido University (Sapporo, Hokkaido, Japan) between February 1998 and April 2004, and cDNA synthesis had already been performed, as described previously (9). All procedures were undertaken after written informed consent had been obtained from each patient, and the study adhered to the ethical guidelines of the dental hospital of the Hokkaido University School of Dentistry (Sapporo, Japan).…”

“…Of the conventional staging and grading systems that are used for the assessment of OSCC tissues, the Yamamoto-Kohama (YK) mode of invasion (5) system can be largely associated with prognosis, particularly with regard to lymph node metastases (6,7). The YK mode of invasion was devised from the grading of the mode of invasion originally described by Jacobson et al (8); in this histological grading, grade 4 is sub-classified into grades 4C and D, whereas evaluation of other grades is the same as defined by Jacobson's classifier (8 YK mode of invasion were evaluated previously and prediction models for the invasion status were constructed (9). Clinical specimens generally originate from different genetic backgrounds, which may have considerable influence on the variation of gene effects.…”