This trend was also observed on the proliferation of the CD4+ CD25+ CD127+ effector T-cell population with significance reached for the majority of GSK2118436 price HNSCC patient subgroups, including advanced stage laryngeal cancer patients (34·59 ± 5·21% versus 23·53 ± 3·83%; P = 0·02) and healthy controls (Table 3). The presence of an immune suppressive Treg cell population has been suggested to be one of the

mechanisms employed by HNSCC to evade the host’s anti-tumour attack.[8] To expand the understanding and role of Treg cells in HNSCC, the current study recruited newly presenting patients that had received no previous diagnosis or treatment for cancer; thereby enabling the direct influence of the head and neck tumour on the Treg cell population to be assessed. Although Treg cells in the peripheral circulation of HNSCC patients have been investigated previously, some studies have included patients who have had previous treatment and have grouped HNSCC patients as a single entity.[11, 12, 26] In the current study the use of the CD127 marker has allowed the determination of both the frequency and the function of Treg cells in the circulation of laryngeal and oropharyngeal cancer patients with tumours of varying stage and nodal status. Foxp3 was expressed by over 80% of the CD25high Treg cells from HNSCC patients, which was significantly higher than healthy controls, this is in accordance with several head and neck cancer publications.[12,

26] For both HNSCC patients and healthy controls, a significantly Palbociclib molecular weight smaller percentage of CD25inter Treg cells expressed Foxp3 compared with the CD25high Treg ADAMTS5 cells; however, the expression of the transcription factor by the CD25inter Treg cell population remained higher in the patients compared with the healthy controls. The frequency of Treg cells in the peripheral circulation of HNSCC patients was similar to that found in healthy controls, regardless of whether the level of expression of CD25 was intermediate or high. This is in contrast to the majority of results reported by other cancer studies

and previous HNSCC investigations where Treg cells have been found to be increased in the cancer patients.[11-16] However, not all cancer publications report an elevated trend, with some observing no significant differences in the frequency of Treg cells in the peripheral circulation of patients and healthy controls, including one study examining oral SCC.[27-29] It is perhaps not surprising that results between studies are inconsistent, with the use of different markers to identify Treg cells, various patient recruitment criteria and a heterogeneous cancer population. These biological and methodological factors are likely to cause differences in reported Treg cell behaviour. Head and neck tumours arising from different subsites are frequently grouped together in research studies, but the various subsites are known to have different aetiologies and survival rates for the same stage of disease.