Whole-exome sequencing reveals genetic underpinnings of salivary adenoid cystic carcinoma in the Chinese population

Single-cell RNA sequencing identifies a paracrine interaction that may drive oncogenic notch signaling in human adenoid cystic carcinoma

Salivary adenoid cystic carcinoma (ACC) is a rare, biologically unique biphasic tumor that consists of malignant myoepithelial and luminal cells. MYB and Notch signaling have been implicated in ACC pathophysiology, but in vivo descriptions of these two programs in human tumors and investigation into their active coordination remain incomplete. We utilize single-cell RNA sequencing to profile human head and neck ACC, including a comparison of primary ACC with a matched local recurrence. We define expression heterogeneity in these rare tumors, uncovering diversity in myoepithelial and luminal cell expression. We find differential expression of Notch ligands DLL1, JAG1, and JAG2 in myoepithelial cells, suggesting a paracrine interaction that may support oncogenic Notch signaling. We validate this selective expression in three published cohorts of patients with ACC. Our data provide a potential explanation for the biphasic nature of low- and intermediate-grade ACC and may help direct new therapeutic strategies against these tumors.

Reconstruction and analysis of the aberrant lncRNA-miRNA-mRNA network based on competitive endogenous RNA in adenoid cystic carcinoma of the salivary gland

Background

The aim of this work was to investigate the competing endogenous RNA (ceRNA) network in adenoid cystic carcinoma of the salivary gland (SACC).

Methods

Differentially expressed lncRNAs (DElncRNAs), miRNAs (DEmiRNAs), and mRNAs (DEmRNAs) between cancer tissues and normal salivary gland (NSG) in ACC were identified using data from the Gene Expression Omnibus (GEO) database. Functional annotation and pathway enrichment analysis of DEmRNAs were performed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. The miRNAs that are targeted by lncRNAs were predicted using miRanda and PITA, while the target mRNAs of miRNAs were retrieved from miRanda, miRWalk, and TargetScan. A protein-protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database, and then we constructed the lncRNA-miRNA-mRNA networks of ACC.

Results

Differentially expressed RNAs were identified in SACC. Upon comparing cancer tissues and NSG tissues, 103 upregulated and 52 downregulated lncRNAs and 745 upregulated and 866 downregulated mRNAs were identified in GSE88804; in addition, 39 upregulated and 43 downregulated miRNAs were identified in GSE117275. GO enrichment analyses revealed that the most relevant GO terms were regulation of transcription DNA-templated, transcription DNA-templated, and cell division. KEGG pathway enrichment analysis showed that differentially expressed genes (DEGs) were mainly enriched in the cell cycle, pathways in cancer, PI3K-Akt signaling pathway, breast cancer, and microRNAs in cancer. The PPI network consisted of 27 upregulated and 54 downregulated mRNAs. By constructing ceRNA network, NONHSAT251752.1-hsa-miR-6817-5p-NOTCH1, NONHSAT251752.1-hsa-miR-204-5p/hsa-miR-138-5p-CDK6 regulatory axises were identified and all genes in the network were verified by qRT-PCR.

Conclusions

The present study constructed ceRNA networks in SACC and provided a novel perspective of the molecular mechanisms for SACC.

Genetic and treatment profiles of patients with concurrent Epidermal Growth Factor Receptor (EGFR) and Anaplastic Lymphoma Kinase (ALK) mutations

Background

EGFR and ALK alternations often contribute to human malignancies, including lung cancer. EGFR and ALK mutations are usually sensitive to EGFR-tyrosine kinase inhibitors (TKIs) and ALK-TKIs. Although generally mutually exclusive, these mutations do co-exist in rare cases. This study investigated the frequencies, clinical characteristics, therapeutic efficacies, and genetic profiles of lung cancer patients with EGFR and ALK co-mutations.

Methods

Patients with concurrent EGFR and ALK mutations were included in this study, which analyzed mutation profiles and treatment histories. SPSS20.0 were used for survival analysis.

Results

Among 271 ALK-positive (ALK-pos) and 2975 EGFR-positive (EGFR-pos) patients in our database, nine (2.6% of ALK-pos and 0.2% of EGFR-pos) patients had concurrent EGFR and ALK mutations (including three exon19 Indel + EML4-ALK, two exon19 Indel + STRN-ALK, two L858R + L1152R, one L858R + EML4-ALK, and one G719C + S768I + STRN-ALK). Eight patients had at least one type of EGFR-TKIs treatment. The median progression free survival (PFS) of these patients on first-generation EGFR-TKIs was 14.5 months (95% CI: 11 - NR). Of these eight patients, one who progressed on Gefitinib and subsequently on Osimertinib had a T790M + C797G. The other seven EGFR-TKIs resistance patients had no known resistance mutations. No patients had ALK mutations before treatment, so ALK mutations may have developed as resistance mechanisms during EGFR-TKIs therapies. EGFR-TKIs-treated patients with EGFR/ALK L1152R mutations generally had a shorter PFS than patients with other mutation combinations.

Conclusions

ALK and EGFR mutations coincide at a relatively low frequency in lung cancer patients. ALK mutations developed either synchronously or heterochronously with EGFR mutations. Two ALK mutations (L1152R and STRN-ALK) may co-exist with EGFR mutations at a higher frequency than others. Most EGFR/ALK co-alteration patients (other than the EGFR/ALK L1152R type) can benefit from first line EGFR-TKIs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08824-2.