Abstract: Objective To examine the association between Helicobacter pylori and laryngeal squamous cell carcinoma(LSCC). Methods Between March 2016 and February 2018, 124 patients were randomly enrolled in this study, including 71 with LSCC and 53 with vocal cord polyps and epiglottic cysts. The expression of H.pylori in tissues was detected with polymerase chain reaction(PCR)technique, and serum H.pylori IgG was detected using enzyme-linked immunosorbent assay(ELISA). The expressions of RASSF1A and FHIT in tissues were detected using immunohistochemistry(IHC)and PCR. The expressions of RASSF1A and FHIT in FaDu cells under H.pylori co-culture conditions were detected using PCR and western blot tests. Results The H.pylori-positive rates in LSCC and control groups were 71.83%(51/71)and 26.42%(14/53)(P<0.001). Six patients(11.76%)only had H.pylori infection in tumor tissues, 24(47.06%)only had infection in adjacent cancer tissues, and 21(41.18%)had H.pylori infection in both tumor and adjacent cancer tissues (P<0.05). Positive rates for H.pylori IgG antibody were 78.87%(56/71)and 64.15%(34/53)in LSCC and control groups(P=0.069). H.pylori infection was a risk factor for LSCC by univariate logistic regression analysis(odds ratio ［OR］=7.09, 95% confidence interval ［CI］: 3.11-17.28, P<0.001). H.pylori infection was an independent risk factor for LSCC by multivariate logistic regression analysis(OR=6.94, 95% CI: 2.87-15.31, P<0.001). Mann-Whitney tests showed no statistically significant differences in H.pylori infection according to different lesion sites, T stages, and TNM stages(P>0.05). The expressions of RASSF1A in LSCC tissues with and without H.pylori infection were 4.46±1.93 and 8.78±1.82(P<0.05)using IHC. The expressions of FHIT in LSCC tissues with and without H.pylori infection were 7.52±1.69, 2.86±1.15(P<0.05)using IHC. The expressions of RASSF1A mRNA in LSCC tissues with and without H.pylori infection were 0.74±0.10 and 0.19±0.06(P<0.05)using quantitative real-time(qRT)-PCR. The expressions of FHIT in LSCC tissues with and without H.pylori infection were 0.42±0.10 and 1.16±0.12(P<0.05)using qRT-PCR. The expressions of RASSF1A mRNA in FaDu cells under H.pylori co-culture conditions(30∶1, 100∶1, 300∶1)were 0.20±0.08, 0.43±0.10, and 1.41±0.08, and FHIT mRNA expressions were 1.26±0.22, 0.70±0.13, and 0.18±0.10 by qRT-PCR. The expressions of RASSF1A mRNA in FaDu cells under H.pylori co-culture conditions(30∶1, 100∶1, 300∶1)were 0.53±0.12, 0.59±0.10, and 1.07±0.14, and FHIT mRNA expressions were 0.69±0.11, 0.42±0.14, and 0.28±0.09 by Western blotting. Conclusion There is significant evidence that H.pylori is present in the mucosa of laryngeal tissues in LSCC. H.pylori may be an important risk factor for the development of LSCC by regulating RASSF1A and FHIT expression.

Key words: Helicobacter pylori, Laryngeal squamous cell carcinoma, RASSF1A, FHIT