**1. Introduction**

Ovarian Cancer is the eighth most common cancer among women worldwide, with an incidence of about 239,000 new cases and 152,000 deaths annually [1]. It is a complex disease with multiple distinct molecular and histologic types, each with different aetiology, risk factors, prognosis and response to treatment. Several factors make ovarian cancer treatment difficult, even though most patients experience or present symptoms, but such symptoms tend to overlap or mimic other symptoms presented in other gynaecological, genitourinary and gastrointestinal diseases. Therefore, early diagnosis is rarely achieved and as such, it is mostly carried out after metastasis [2].

Almost all malignant and benign ovarian tumours are of epithelial, stromal or germ cell origin, with those of epithelial origin accounting for more than 90% [3]. Malignant ovarian cancers also referred to as carcinomas are classified into five main histologic types (histotypes) namely: endometroid, mucinous, clear cell, low-grade serous and


### **Table 1.**

*Salient features of histological subtypes of epithelial ovarian carcinomas.*

high-grade serous ovarian carcinoma (**Table 1**). The pathogenesis and origin of ovarian cancer are not well understood. However, most tumours appear to originate from other parts of the reproductive system and affect the ovary secondarily [4].

One of the most common genetic abnormality seen in ovarian cancer is mutation and loss of *TP53* function, including DNA copy number abnormalities which affects cell proliferation and apoptosis [2].

Despite the continuous effort to develop early screening strategies, only a negligible fraction of ovarian cancers are diagnosed while they are localized to the ovaries. Diagnosis is mostly made after the disease has spread to the pelvic organs, abdomen, and/or beyond the peritoneal cavity, and this makes treatment difficult.

The standard treatment of ovarian cancer is platinum and taxane-based combination chemotherapy after cytoreductive surgery to remove a significant bulk of the tumour. Despite being considered chemosensitive, the majority of the patients subjected to cytoreductive surgery and combination therapy will need second-line chemotherapy due to tumour recurrence within 2 years [5].
