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Background Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignant tumor worldwide with high morbidity and mortality. However, the diagnosis and molecular mechanisms of HNSCC remains poor. Methods Robust rank aggregation method was performed to excavate the differentially expressed genes (DEGs) in five datasets (GSE6631, GSE13601, GSE23036, GSE30784, GSE107591) from the Gene Expression Omnibus. Search Tool for the Retrieval of Interacting Genes (STRING) database extracted hub genes from the protein‐protein interaction network. The expression of the hub genes was validated using expression profile from The Cancer Genome Atlas and Oncomine database. The module analysis and disease‐free survival analysis of the hub genes were analyzed by Cytoscape and the Kaplan‐Meier curve, respectively. The expression of hub genes was verified in clinical specimens. The functions of MMP1 which is most important in hub genes were explored in vitro and in vivo. Results Totally, 235 DEGs were identified in the present study which consists of 103 up‐regulated and 132 down‐regulated genes which were significantly enriched in the molecular function of calcium ion binding followed in the biological process of skin development. The mainly enriched pathways were ECM (extracellular matrix)‐receptor interaction (hsa04512) and protein digestion and absorption (hsa04974). Six hub genes were screened out which showed dramatically increased expression in HNSCC samples compared with normal samples, including COL4A1, MMP1, PLAU, RBP1, SEMA3C, and COL4A2. These hub genes all showed worse disease‐free survival with higher expression and were up‐regulated in HNSCC clinical samples. MMP1 was proved to promote cell growth, migration, and phosphorylation of AKT in vitro and to promote liver metastasis in vivo. Conclusion Bioinformatics analysis identified six key genes in HNSCC. Of these, MMP1 is the most likely biomarker. It activates the AKT pathway and promotes tumor progression.

Background Hypopharyngeal cancer accounts for 2% in head and neck cancers and has a poor prognosis. Cisplatin is a widely used chemotherapeutic drug in kinds of carcinomas, concluding hypopharyngeal cancer. However, the resistance of cisplatin appeared in recent years. Cisplatin-resistance has been partly explored before, but rarely in hypopharyngeal cancer. Methods We cultured the hypopharyngeal cancer cell (FaDu) and induced its cisplatin-resistant cell (FaDu/DDP4). Then we tested the differentially expressed genes (DEGs) between FaDu and FaDu/DDP4. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were conducted on the DEGs, and we drew the ceRNA networks of DEGs. Finally, we chose eight miRNAs and six mRNAs for qRT-PCR to verify our microarray. Results We induced cisplatin-resistant FaDu/DDP4 and proved its chemoresistance. The resistance index (RI) of FaDu/DDP4 was 2.828. DEGs contain 2,388 lncRNAs, 1,932 circRNAs, 745 mRNAs and 202 miRNAs. These 745 mRNAs were classified into three domains and 47 secondary GO terms. In KEGG pathway enrichment, the “TNF signaling pathway”, “IL-17 signaling pathway” and “JAK-STAT signaling pathway” were potentially significant signaling pathways. Then, 52 lncRNAs, 148 circRNAs, 155 mRNAs and 18 miRNAs were selected to draw the network. We noticed several potential targets (as miR-197-5p, miR-6808-5p, APOE, MMP1, S100A9 and CYP24A1). At last, the eight miRNAs and six mRNAs that are critical RNAs in ceRNA network were verified by qRT-PCR. Conclusion The microarray helped to find DEGs in cisplatin-resistant hypopharyngeal cancer. TNF, IL-17 and JAK-STAT signaling pathways might be more significant for cisplatin-resistance. MiR-197-5p, miR-6808-5p, APOE, MMP1, S100A9 and CYP24A1 might be potential genes inducing resistance.