Detection of novel Human papilloma virus type 82 in laryngeal cancer: case report

A possible interplay between HR-HPV and stemness in tumor development: an in vivo investigation of CD133 as a putative marker of cancer stem cell in HPV18-infected KB cell line

High-risk HPVs (HR-HPVs) are DNA viruses considered as primary etiologic factors in malignancies of the low female genital tract. Their presence has also been documented in oropharyngeal and laryngeal cancers. However, HPV infection is considered a necessary but not sufficient cause of tumoral development; meantime, increasing evidences on the tumorigenic role of cancer stem cells (CSCs) have been documented in the literature. CSCs represent a small subpopulation of neoplastic cells with self-renewal potential, capable of maintaining tumor growth and cell differentiation, also involved in metastatic process, recurrence, and resistance to chemotherapeutic agents. In the present study, performed on KB cell lines, we evaluated the tumor forming potential of CSCs, and their relationship with the HPV infection status. We started our study by identifying the most aggressive cell line on the minimal number of cells being able of growth in vivo in a model of athymic nude mice (BALB/c nu/nu). We used an oral-derived KB cell line separated in the KB-CD133+ and KB-CD133- populations, by using immunomagnetic beads and fluorescence-activated cell sorting (FACS). The separated populations were injected in athymic nude mice (BALB/c nu/nu). Xenograft tumors have been analyzed for tumor size, CD133 expression by immunohistochemistry (IHC) and for DNA HR-HPV integration by in situ hybridization (ISH), comparing CD133-enriched xenograft tumors versus the CD133 non-enriched ones. On standard conditions, the KB cell line has a poor population of glycosylated CD133 marker (<5.0%) when investigated with antibodies versus CD133, and more specifically its glycosylated epitope (AC133). Enriched CD133 KB cells possess a higher capacity of tumor growth in xenograft models of nude mice when compared to KB CD133-negative cells. We observed that the AC133 epitope, extensively used to purifying hematopoietic stem cells, is able to select an epithelial subpopulation of cancer stem cells with aggressive behavior. We retain that CD133 may be a useful target in anticancer strategies including pharmacological and immunological therapies.

Biological evidence for a causal role of HPV16 in a small fraction of laryngeal squamous cell carcinoma

BACKGROUND

Human papillomavirus (HPV) is a causal factor in virtually all cervical and a subset of oropharyngeal squamous cell carcinoma (OP-SCC), whereas its role in laryngeal squamous cell carcinoma (L-SCC) is unclear.

METHODS

Formalin-fixed paraffin-embedded (N=154) and deep-frozen tissues (N=55) of 102 L-SCC patients were analysed for the presence of 51 mucosal HPV types. HPV DNA-positive (HPV DNA+) cases were analysed for E6*I mRNA transcripts of all high risk (HR)/probably/possibly (p)HR-HPV identified, and for HPV type 16 (HPV16) viral load. Expression of p16(INK4a), pRb, cyclin D1 and p53 was analysed by immunohistochemistry.

RESULTS

Ninety-two patients were valid in DNA analysis, of which 32 (35%) had at least one HPV DNA+ sample. Among the 29 single infections, 22 (76%) were HPV16, 2 (7%) HPV56 and 1 each (4%) HPV45, HPV53, HPV70, HPV11 and HPV42. Three cases harboured HPV16 with HPV33 (twice) or HPV45. Only 32% of HPV DNA+ findings were reproducible. Among HPV16 DNA+ L-SCC, 2 out of 23 (9%) had high viral loads, 5 out of 25 (21%) expressed E6*I mRNA and 3 out of 21 (14%) showed high p16(INK4a) and low pRb expression (all three HPV16 RNA-positive), immunohistochemical marker combination not identified in any other HPV DNA+ or HPV DNA-negative (HPV DNA-) L-SCC, respectively.

CONCLUSION

HPV type 16 has a causative role in a small subgroup of L-SCC (<5% in this German hospital series).

An unusual human papillomavirus type 82 detection in laryngeal squamous cell carcinoma: case report and review of literature

Squamous cell carcinoma (SCC) of the larynx is extremely rare in adolescent or younger adult and typically has an aggressive nature. The mechanism of laryngeal oncogenesis is complex and little is known about the role of human papillomaviruses (HPVs) in SCC in young age. HPV infection may occur during birth or latter by oro-genital contact. Most HPV genotypes detected were HPV 6, 11, 16, 18, 33 and 51. Herein, we report a case of invasive laryngeal SCC expressing an HPV 82 in an 18 year-old man with a history of unexplored severe acute dysphonia that started in early childhood.