Abstract

   Head and neck cancer (HNC) tumorigenesis involves a combination of
   multiple genetic alteration processes. Tumour necrosis
   factor-alpha-induced proteins (TNFAIPs) are involved in tumour
   development and progression, but few studies have been conducted on
   these factors in HNC. We aimed to analyse TNFAIPs and assess their
   potential as prognostic biomarkers and therapeutic targets using the
   Oncomine, UALCAN, Human Protein Atlas, LinkedOmics, cBioPortal,
   GeneMANIA, Enrichr, and Tumor IMmune Estimation Resource databases. We
   found that the transcript levels of TNFAIP1, TNFAIP3, EFNA1, TNFAIP6
   and TNFAIP8 were increased, while those of TNFAIP8L3 and STEAP4 were
   reduced in HNC tissues versus normal tissues. The EFNA1, TNFAIP8 and
   TNFAIP8L3 expression levels were significantly correlated with the
   pathological stage. In HNC patients, high PTX3 and TNFAIP6 transcript
   levels were significantly associated with shorter overall survival
   (OS). Moreover, genetic alterations in TNFAIP1, TNFAIP6, and STEAP4
   resulted in poorer disease-free survival, progression-free survival,
   and OS, respectively. TNFAIPs may mediate HNC tumorigenesis by
   regulating PI3K-Akt, Ras and other signalling pathways. TNFAIPs are
   also closely correlated with the infiltration of immune cells,
   including B cells, CD8^+ T cells, CD4^+ T cells, etc. The data above
   indicate that TNFAIPs may be potential biomarkers and therapeutic
   targets for HNC.

   Subject terms: Head and neck cancer, Prognostic markers

Introduction

   Head and neck cancer (HNC) is the seventh most common malignancy
   worldwide, with more than 890,000 new cases and 450,000 deaths per
   year^[38]1,[39]2. HNC includes tumours arising in the lip, mouth,
   paranasal sinus, oropharynx, nasopharynx and hypopharynx. Squamous cell
   carcinoma is the histologic type in more than 90% of HNC cases.
   Surgery, chemotherapy, and radiotherapy are the main treatments for
   HNC, and great progress in these fields has been made in recent years,
   which has improved the long-term survival rates of early-stage patients
   to approximately 70–90%^[40]1. However, 5-year survival rate remains
   less than 40% in advanced or metastatic patients^[41]3. In addition,
   routine therapies may affect organ function and damage structures
   related to speaking and swallowing, causing a severe decline in the
   quality of life of HNC patients. Therefore, new therapies are needed to
   compensate for the shortcomings of conventional treatments. At present,
   the prognosis of HNC mainly depends on the tumour-node-metastasis (TNM)
   stage. However, the TNM stage is based on anatomical information and
   does not reflect the biological heterogeneity of HNC. Hence, it is
   urgent to find new biomarkers that can act as prognostic indicators to
   guide precise individualized treatment. In recent years, researches on
   targeted therapy have been performed, and PD-1 immune checkpoint
   inhibitors have been developed^[42]4,[43]5. The anti-PD-1 antibodies
   pembrolizumab and nivolumab showed durable responses and survival
   improvements in patients with recurrent or metastatic HNC, leading to
   approval of these two agents by the FDA in 2016^[44]1,[45]6. However,
   immunotherapy is only suitable for some patients and thus cannot meet
   clinical needs. Therefore, more therapeutic targets and prognostic
   biomarkers should be identified.

   Tumour necrosis factor-alpha-induced proteins (TNFAIPs) were initially
   identified as tumour necrosis factor-alpha- and
   lipopolysaccharide-induced genes in endothelial cells^[46]7–[47]9. The
   TNFAIP family members include TNFAIP1, TNFAIP2, TNFAIP3, EFNA1, PTX3,
   TNFAIP6, TNFAIP8, TNFAIP8L1, TNFAIP8L2, TNFAIP8L3, and STEAP4, which
   are involved in immune reactions, inflammatory responses, signal
   transduction, apoptosis, differentiation, material transport and other
   biological functions. They play important roles in multiple diseases,
   especially malignant tumours^[48]8,[49]10,[50]11. Several TNFAIPs are
   deeply involved in the immune and inflammatory processes of cancer. For
   example, TNFAIP1 induces cervical cancer cell apoptosis by inhibiting
   the NF-κB signalling pathway^[51]12. Inflammation induces copper uptake
   via the STEAP4/IL-17/XIAP axis, which promotes the tumorigenesis and
   progression of colon cancer^[52]13. PTX3 regulates complement system
   activation by interacting with complement regulator H, resulting in
   C3a- and C5a-mediated recruitment of macrophages and promotion of IL-1β
   and IL-17 secretion, which leads to the inflammatory activation of
   malignant disease^[53]14. Moreover, PTX3 is also a key target of the
   NF-κB signalling pathway and regulates inflammatory processes in breast
   cancer^[54]15. Previous studies found that TNFAIP8 was overexpressed in
   CD4^+ and CD8^+ T cells in patients with lung cancer^[55]16, suggesting
   that TNFAIP8 might be involved in the regulation of tumour immune
   status. It has been reported that differentially expressed TNFAIPs have
   prognostic value in multiple malignant diseases^[56]17–[57]19. Zhang et
   al.^[58]17 reported that overexpression of TNFAIP1 was associated with
   a poor prognosis in breast cancer. TNFAIP2 highly expressed in classic
   Hodgkin's lymphoma and mediastinal diffuse large B-cell lymphoma and is
   associated with the progression of these malignant diseases^[59]20. In
   addition, EFNA1 expression is upregulated in gastric cancer,
   oesophageal squamous cell carcinoma, hepatocellular carcinoma, cervical
   cancer and ovarian cancer^[60]21–[61]25 and is positively correlated
   with a poor prognosis.

   The expression profiles of several TNFAIPs in HNC have been reported in
   previous studies^[62]26–[63]28. However, the underlying mechanism by
   which TNFAIPs are activated or inhibited and the distinct functions of
   TNFAIPs in HNC have yet to be fully elucidated. Therefore, it is of
   great significance to clarify the value of TNFAIPs as prognostic
   biomarkers and therapeutic targets for HNC. In this study, we used
   several large databases to analyse the expression of TNFAIPs and assess
   their potential as prognostic biomarkers to provide a scientific basis
   for personalized medicine for HNC.

Results

Differentially expressed TNFAIPs in HNC patients

   We explored the transcript levels of eleven TNFAIPs in HNC and normal
   tissues using Oncomine. The results are presented in Fig. [64]1 and
   Table [65]1. According to the results above, the transcript levels of
   TNFAIP1, TNFAIP3, EFNA1, PTX3, TNFAIP6, and TNFAIP8 were significantly
   upregulated, while the transcript levels of TNFAIP8L1, TNFAIP8L3, and
   STEAP4 were significantly downregulated in HNC tissues compared with
   normal tissues (all P < 0.05). Dataset-based analysis of cancer versus
   normal samples showed that TNFAIP1 expression was increased with fold
   changes of 2.230 and 2.190 in 31 cases of tongue squamous cell
   carcinoma tissues and 15 cases of tongue carcinoma^[66]26,[67]29. The
   expression of TNFAIP3 was upregulated by a fold change of 2.051 to
   5.457 in tissues from 247 patients with HNC in nine
   datasets^[68]26–[69]31. EFNA1 expression was increased 2.329-fold to
   5.986-fold in HNC tissues from 68 patients^[70]29,[71]30,[72]32. PTX3
   was also overexpressed with fold changes of 4.481 and 3.883 in tissues
   from 34 and 41 patients with HNC, respectively^[73]27,[74]30. Analysis
   of six datasets revealed that TNFAIP6 expression was increased by a
   fold change of 2.047 to 4.998 in 193
   patients^[75]27,[76]28,[77]30,[78]33–[79]35. Moreover, TNFAIP8
   expression increased by 2.427-fold to 3.899-fold in tissues from 76
   patients with HNC^[80]26,[81]29,[82]31. In contrast, the expression
   levels of TNFAIP8L1, TNFAIP8L3, and STEAP4 were downregulated, with
   fold changes of 2.735, 2.233, and 2.587, respectively, in 94 HNC
   samples^[83]26,[84]28,[85]34. However, the transcript levels of TNFAIP2
   and TNFAIP8L2 were not significantly different between cancer samples
   and normal samples. We further evaluated the expression levels of
   TNFAIPs in 520 HNC and 44 normal samples by the UALCAN database. As
   expected, the transcript levels of TNFAIP1, TNFAIP2, TNFAIP3, EFNA1,
   TNFAIP6, TNFAIP8, TNFAIP8L1 and TNFAIP8L2 were significantly elevated
   in HNC samples versus normal samples, while the transcript levels of
   TNFAIP8L3 and STEAP4 were significantly reduced (Fig. [86]2, all
   P < 0.05).

Figure 1.

   [87]Figure 1
   [88]Open in a new tab

   mRNA levels of TNFAIPs in HNC. The figure shows the numbers of datasets
   with statistically significant upregulation (red) or downregulation
   (blue) of TNFAIPs at the mRNA level (Oncomine).

Table 1.

   The mRNA levels of TNFAIPs in different types of HNC tissues and normal
   tissues (Oncomine).
   TNFAIPs Types Fold change P value T test References