Ovarian Cancer Genomics

**3**

**Chapter 1**

**Abstract**

**1. Introduction**

tic and therapeutic support [4].

Therapy

Ovarian Cancer: Molecular

Classification and Targeted

Ovarian cancer is the deadliest gynecological cancer among women with an overall 5-year survival rate below 50% due to its asymptomatic nature, diagnosis at advanced stages, and a high recurrence rate after standard therapy in 70% of cases. Ovarian cancers are heterogenous cancers where each subtype possesses a varied morphology and biologic behavior. Accumulating evidence has identified each of these subtypes characterized with specific pathways activated in each along with specific gene alterations. For example, high-grade serous ovarian cancer is characterized by universal *TP53* mutation, mucinous ovarian cancer with *KRAS* mutation and clear cell or endometrioid ovarian cancers with *ARID1A* mutations. With the current focus of molecular-targeted therapies for cancer, such druggable markers serve as excellent targets for precision therapy and combination therapy. This chapter, provides an overview of the critical molecular pathways activated in the ovarian cancer subtypes with its druggable targets studied in ovarian cancer. We also highlight the implications of miRNAs in chemoresistance and sensitivity in the regulation of ovarian cancer.

**Keywords:** ovarian cancer subtypes, targeted therapy, miRNAs in ovarian cancers

Ovaries are the prime female reproductive organ that produces the oocyte or the egg cell for fertilization. It is also an endocrine gland that produces the female sex hormones estrogen and progesterone responsible for ovulation and pregnancy maintenance. Some of the diseases that affect the ovaries are ovarian cysts, primary ovarian insufficiency, ovarian torsion and more recently ovarian cancer (OC). OC was first detected in the 1950s and is now one of the deadliest gynecological cancers among women [1, 2]. According to the latest Global Cancer Observatory: CANCER TODAY (GLOBOCAN 2018), the incidence and mortality rates of OC vary globally and ranks at the 8th and 7th position respectively [3]. The highest mortality rates are reported in Oceania and Europe and the lowest are from Latin America, the Caribbean and Asia [3]. OCs are also prevalent in countries with a high human development index (HDI) but with lower mortality rates due to increased diagnos-

Most OCs manifest post menopause and the increased incidence is reported in women older than 65 years [5]. Considering the ethnicity, non-Hispanic white women are reported to have the highest incidence and mortality rates [6]. OCs are heterogeneous cancer, hence the risk factors for each histological subtype vary. In

*Febina Ravindran and Bibha Choudhary*
