Affymetrix U133plus2 GeneChips were used to profile 59 head and neck squamous cell cancers. A hypoxia metagene was obtained by analysis of genes whose in vivo expression clustered with the expression of 10 well-known hypoxiaregulated genes (e.g., CA9, GLUT1, and VEGF). To minimize random aggregation, strongly correlated up-regulated genes appearing in >50% of clusters defined a signature comprising 99 genes, of which 27% were previously known to be hypoxia associated. The median RNA expression of the 99 genes in the signature was an independent prognostic factor for recurrence-free survival in a publicly available head and neck cancer data set, outdoing the original intrinsic classifier. In a published breast cancer series, the hypoxia signature was a significant prognostic factor for overall survival independent of clinicopathologic risk factors and a trained profile. The work highlights the validity and potential of using data from analysis of in vitro stress pathways for deriving a biological metagene/gene signature in vivo. [Cancer Res 2007;67(7):3441-9]

Background:To investigate small-nucleolar RNAs (snoRNAs) as reference genes when measuring miRNA expression in tumour samples, given emerging evidence for their role in cancer.Methods:Four snoRNAs, commonly used for normalisation, RNU44, RNU48, RNU43 and RNU6B, and miRNA known to be associated with pathological factors, were measured by real-time polymerase chain reaction in two patient series: 219 breast cancer and 46 head and neck squamous cell carcinoma (HNSCC). SnoRNA and miRNA were then correlated with clinicopathological features and prognosis.Results:Small-nucleolar RNA expression was as variable as miRNA expression (miR-21, miR-210, miR-10b). Normalising miRNA PCR expression data to these recommended snoRNAs introduced bias in associations between miRNA and pathology or outcome. Low snoRNA expression correlated with markers of aggressive pathology. Low levels of RNU44 were associated with a poor prognosis. RNU44 is an intronic gene in a cluster of highly conserved snoRNAs in the growth arrest specific 5 (GAS5) transcript, which is normally upregulated to arrest cell growth under stress. Low-tumour GAS5 expression was associated with a poor prognosis. RNU48 and RNU43 were also identified as intronic snoRNAs within genes that are dysregulated in cancer.Conclusion:Small-nucleolar RNAs are important in cancer prognosis, and their use as reference genes can introduce bias when determining miRNA expression.

Purpose: Tumor hypoxia is associated with a poor prognosis, hypoxia modification improves outcome, and hypoxic status predicts benefit from treatment. Yet, there is no universal measure of clinical hypoxia. The aim of this study was to investigate whether a 26-gene hypoxia signature predicted benefit from hypoxiamodifying treatment in both cancer types.Experimental Design: Samples were available from 157 T2-T4 laryngeal cancer and 185 T1-T4a bladder cancer patients enrolled on the accelerated radiotherapy with carbogen and nicotinamide (ARCON) and bladder carbogen nicotinamide (BCON) phase III randomized trials of radiotherapy alone or with carbogen and nicotinamide (CON) respectively. Customized TaqMan low density arrays (TLDA) were used to assess expression of the 26-gene signature using quantitative real-time PCR. The median expression of the 26 genes was used to derive a hypoxia score (HS). Patients were categorized as TLDA-HS low ( median) or TLDA-HS high (>median). The primary outcome measures were regional control (RC; ARCON) and overall survival (BCON).Results: Laryngeal tumors categorized as TLDA-HS high showed greater benefit from ARCON than TLDA-HS low tumors. Five-year RC was 81% (radiotherapy alone) versus 100% (CON) for TLDA-HS high (P ¼ 0.009). For TLDA-HS low, 5-year RC was 91% (radiotherapy alone) versus 90% (CON; P ¼ 0.90). TLDA-HS did not predict benefit from CON in bladder cancer.Conclusion: The 26-gene hypoxia signature predicts benefit from hypoxia-modifying treatment in laryngeal cancer. These findings will be evaluated in a prospective clinical trial.