Head and neck cancers (HNSCC) are primarily squamous cell cancers represented by tumors of
the upper aerodigestive tract. Locally advanced stages (stages III and IV) account for 50 to
70% of all presentations. The three main risk factors are smoking, alcohol and oropharyngeal
infection with human papilloma virus (HPV).
Apart from HPV status, there is no biomarker for the prognosis in HSNCC patients. Circulating
Tumor Cells (CTCs) can provide "real-time" information on tumor behavior and are already used
in various cancers (colon, lung). Their detection has limited sensitivity and biomarkers
cannot be used for early diagnosis, but may be useful during follow-up to assess local,
regional or metastatic early tumor recurrence.
By using blood samples at different times (at diagnosis, after initial treatment and during
follow-up), we will be able to measure the variation in quantification and establish a
predictive role of these CTCs for the response to treatment.
Our hypothesis is that CTCs may have a key role, in addition to clinical and radiological
examination, in detecting early tumor relapse.
We believe that the joint consideration of clinical parameters, treatment strategy and
quantification of CTCs could optimize patient follow-up and management.
The CTC extraction system, ClearCell® FX from Biolidics, is an automated microfluidic
enrichment system. It has the advantage of recovering fully intact and viable CTCs from a
standard blood sample. The gentle sorting principle allows to preserve cell integrity and
thus the expression of surface antigens. The CTCs thus isolated can then be re-cultured or
analyzed by immunostaining. This high-performance technique, in operation since December 2017
in the Biochemistry Department of Pr Claire Rodriguez-Lafrasse (HCL), has demonstrated its
usefulness in lung cancer.
Transcriptomic analysis of CTCs can be performed at the scale of a cell after isolation of
the CTCs. CTCs can then be sequenced in RNAseq either in bulk (pool of cells) or cell by cell
on our Illumina (Nextseq) sequencer, in order to define the heterogeneity of the tumor.
Transcriptome analysis then provides information on the state of the cell as to its position
in the epithelio-mesenchymal transition thanks to a molecular signature by phenotype. A
priori-free characterization is therefore possible thanks to the RNAseq single-cell. This
highly sensitive and innovative technique will allow the study of the gene expression profile
of CTCs.