Introduction
While laryngeal cancer makes up 30-40% of head and neck malignancies and 1-2.5% of all malign cancers [1]. Every year, head and neck cancers are seen in more than half a million people worldwide, and one-fourth of these cases consists of laryngeal squamous cell carcinomas (LSCC) [2]. According to the GLOBOCAN 2018 data, the incidence and mortality rates of laryngeal cancer (100.000 per person, standardized rates according to age) are 3.6/100.000 and 1.9/100.000 in males and; 0.5/100.000 and 0.3/100.000 in females respectively [3]. It has been reported that laryngeal cancer is seen 7 times more frequently in males and it makes up 1% of deaths related to malignancies in the population and 1.6% in males [4]. Laryngeal carcinomas are 95-98% squamous cell carcinomas (SCC), and it takes the second place after lung cancer in respiratory system malignancies [2].
LSCC has high recurrence, metastasis and mortality rates [2]. Approximately 60% of patients are advanced (Stage III and IV) at the time of diagnosis [5]. Although the incidence of laryngeal cancer has declined, the 5-year survival rate has dropped from 66% to 63% in the last 40 years [6]. When all these factors are considered, understanding the pathogenesis of this cancer, determining its prognostic parameters and the markers related to these parameters are quite important.
Heat shock proteins, a large chaperon protein group (Heatshock-related 70-kDa protein) (HSP), are divided into a few different subgroups according to some of their characteristics [7]. They have a protective function for the cell by creating HSP adaptation mechanisms and it makes an important step in the defense system [8]. HSPA (HSP70), make up the largest group of HSP’s and the genes for this family display many different functions, localization and expression [7]. HSPA-2, also known as HSP70-2 in HSPA family is a significant member that has not been studied yet. It has been defined as a protein specific to the testicles having a fundamental role in primary spermatocytes and spermatogenesis in spermatids for the first time [9]. In addition, it has been reported that HSPA-2 can be seen in non-testicular tissues and has an important role especially in carcinogenesis, and is necessary for tumor growth [10].
In the literature, there are various studies on this topic in different organs [11-17]. The number of studies on the prognostic role of HSPA in LSCC is very few [8]. Besides, we did not find any study investigating the prognostic role of HSPA-2 in LSCC in the literature. In our study, the aim was to examine the relationship between HSPA-2 expression and clinicopathological prognostic parameters in LSCC.