Overexpression of Prothymosin Alpha Predicts Poor Disease Outcome in Head and Neck Cancer

In our recent study, tissue proteomic analysis of oral pre-malignant lesions (OPLs) and normal oral mucosa led to the identification of a panel of biomarkers, including prothymosin alpha (PTMA), to distinguish OPLs from histologically normal oral tissues. This study aimed to determine the clinical significance of PTMA overexpression in oral squamous cell hyperplasia, dysplasia and head and neck squamous cell carcinoma (HNSCC).Immunohistochemistry of PTMA protein was performed in HNSCCs (n = 100), squamous cell hyperplasia (n = 116), dysplasia (n = 50) and histologically normal oral tissues (n = 100). Statistical analysis was carried out to determine the association of PTMA overexpression with clinicopathological parameters and disease prognosis over 7 years for HNSCC patients.<0.001). Chi-square analysis showed significant association of nuclear PTMA with advanced tumor stages (III+IV). Kaplan Meier survival analysis indicated reduced disease free survival (DFS) in HNSCC patients (p<0.001; median survival 11 months). Notably, Cox-multivariate analysis revealed nuclear PTMA as an independent predictor of poor prognosis of HNSCC patients (p<0.001, Hazard's ratio, HR = 5.2, 95% CI = 2.3–11.8) in comparison with the histological grade, T-stage, nodal status and tumor stage.Nuclear PTMA may serve as prognostic marker in HNSCC to determine the subset of patients that are likely to show recurrence of the disease

Analysis of PTMA protein expression in Normal oral mucosa and correlation with clinicopathological parameters.

<p>*Tobacco consumption habits were available for 69 subjects. RMT, retromolar trigone; FOM, floor of mouth.</p

Biomarker analysis of PTMA in squamous cell hyperplasia, dysplasia and HNSCC.

<p>Biomarker analysis of PTMA in squamous cell hyperplasia, dysplasia and HNSCC.</p

Analysis of PTMA protein expression in squamous cell hyperplasia and correlation with clinicopathological parameters.

<p>*Normal vs. squamous cell hyperplasia;</p><p>**Tobacco consumption habits include tobacco chewing (betel quid, areca nut or pan masala) and/or smoking of bidi or cigarettes.</p

Analysis of PTMA protein expression in dysplasia and correlation with clinicopathological parameters.

<p>*Normal vs. dysplasia; Squamous cell hyperplasia vs. dysplasia, p = 0.097;</p><p>**Tobacco consumption habits include tobacco chewing (betel quid, areca nut or pan masala) and/or smoking of bidi or cigarettes.</p

Verification of PTMA overexpression:

<p>(a) RT-PCR analysis of PTMA in normal mucosa, squamous cell hyperplasia, dysplasia and HNSCC tissues. Panel shows increased levels of PTMA transcripts in squamous cell hyperplasia (H1, H2), dysplasia (D1, D2) and HNSCC (T1, T2, T3) compared with the normal oral mucosa (N1, N2) that showed basal levels of PTMA transcripts. β-actin was used as a control to normalize the quantity of RNA used for each RT-PCR reaction is shown in the lower panel. (<b>b</b>) <b>Immunoblot analysis:</b> Immunoblot analysis of PTMA in normal oral mucosa (N1, N2), squamous cell hyperplasia (H1, H2), dysplasia (D1, D2) and HNSCC (T1, T2). Equal amount of protein lysates were electrophoresed on 12% SDS-PAGE and transferred to PVDF membrane. The membrane was incubated with respective primary antibodies and secondary antibodies as described in the Methods section and the signal detected by enhanced chemiluminescence method. Panel shows increased expression of PTMA in squamous cell hyperplasia (H1, H2), dysplasia (D1, D2) and HNSCC (T1, T2) compared with normal oral mucosa (N1, N2). GAPDH was used as loading control (lower panel).</p

Analysis of PTMA protein expression in HNSCC and correlation with clinicopathological parameters.

<p>*Normal vs. HNSCC;</p><p>**Tobacco consumption habits include tobacco chewing (betel quid, areca nut or pan masala) and/or smoking of bidi or cigarettes.</p