Immunotherapy
of HPV induced HNC represents a new treatment approach that might allow clinicians to use conventional treatment at
lower doses, and reduce treatment-related toxicity. Therapy is directed at the oncoproteins E6 and E7 that are expressed
by tumor cells.
Prophylactic vaccination against HPV induces
antigen-specific B cells that can
prevent initial infections. In contrast, therapeutic vaccines generate
CD8+ HPV-specific T cell immune response against E6 and E7 oncoproteins.
Their
role in prevention of HPV-related oropharyngeal cancers is currently being
evaluated, with one trial showing promising results.
Several vaccination therapies are under investigation in HPV-associated HNC. DNA
vaccines produce non-living antigens able to induce cytotoxic T cell, and Th
and B cell immunity. Several DNA
vaccine trials targeting HPV are being tested in cervical cancer.
Peptide vaccines incorporate amino acid sequences that are synthesized to form an
immunogenic peptide molecule representing the specific epitope of a
tumor-associated antigens that binds onto human leukocyte antigen.
(http://www.ncbi.nlm.nih.gov/pubmed/14647479). Several peptide vaccines are
under evaluation in HPV+ HNC..
Vaccination
strategies involving Dendritic cells are also currently being assessed in HPV+
HNC. Activated DCs cells are injected back into the patient 5to kill the cancer
(http://www.ncbi.nlm.nih.gov/pubmed/26351330). Several bacterial HPV vaccines
targeting E6 and E7 have been developed.
Finally,
adoptive T-cell transfer (ACT) might be a promising immunotherapy strategy for
HPV HNC; it involves harvesting and ex vivo expansion of the patient’s own
tumor antigen specific T-cells. Subsequently, T-cells are re-introduced to the
patient, with the view to enhance immunity and improve anticancer immune
response.
It
is hopeful that these novel immunotherapy strategies of HPV positive HNC will
improve patient outcome.
