**1. Introduction**

Cancer is the one of the major death cause worldwide and accounted nearly 10 million deaths in 2020 [1]. The rate of incidence in prostate cancer and bladder cancer are increasing worldwide too. According to GLOBOCON 2018, prostate cancer is the second most frequent cancer and in men, it is fifth leading cause of death. Bladder cancer is also common in men ranking on sixth position and ninth leading cause of cancer death [2]. There are so many treatments available like radiotherapy, chemotherapy, hormonal therapy but these treatments are associated with adverse side effects and poor quality of post treatment life. Hence there is need in development of effective, safe and economically viable antitumor drugs.

Prostate cancer and bladder cancer are heterogeneous diseases where many molecular, environmental and genetic factors are involved in its progression and understanding the mechanism of this progression is difficult [3]. In recent years the cancer research has made significant progress, but many challenges remain as it is [4]. Currently, only 7% of potential anticancer drugs are gaining approval which is much lower than drugs for other diseases [5]. Hence, to improve this percentage, it is essential to clinically approve drugs which are tested in preclinical studies and enabling them to enter phase I clinical trials [6].

Experimental models are important tools in the cancer research. The model should be reproducible, able to successfully reflect disease stage that is being studied and mimic the disease; how it behaves in humans [4]. Cell lines are *in vitro* model systems, a necessary tool, in not only the search for new substances showing antitumor activity but additionally for assessing their effectiveness. They are widely used in different fields of medical research and pharmaceutical companies. Presently pharmaceutical industries mostly rely on *in vitro* models like two dimensional (2D), three dimensional (3D), boyden's chamber (to study chemotaxis and assessment of cell motility) [7], micro fluidic systems (It is small devices that can provide a specific fluid flow, constant temperature, fresh medium, flow pressure and chemical gradients which is same as *in vivo* systems to study migration and invasion [8], 3D bioprinting (mimics the processes that occurs in tumor micro environment) [9, 10]. Main reason for accepting *in vitro* model is it's physiological relevance, it helps in improving the understanding of prognosis and treatment, it provides accuracy and it is also a low cost screening tool for researchers [11]. The usefulness of *in vitro* models is primarily linked to their ability to provide an indefinite source of biological material for experimental purposes. The *in vivo* model involves animals which provide valuable information to understand many aspects in development of disease and initial development of drugs such as toxicity, corrosion and drug activity [12]. But from past two decades, alternatives have been sought due to the fact that animals do not effectively model humans in *in vivo* conditions, as it shows unexpected responses like anatomical variation and also difficulty in extracting quantitative mechanistic data in the studies. Mathematical models are also used in the cancer research to analyze tumor growth and progression, and helps in predicting the effects of some therapies [13]. Different clinical setting, cancer resistance and switching to another treatment, existence of unknown biological details these issues can affect the mathematical models [14–16]. Computer simulation is another model in the cancer research, helps to test complex multi scale cancer progresses, it also accounts for drug pharmacokinetics and pharmacodynamics, but has drawback in less common cancers because of less data, therefore it lacks perspective validation and accuracy [17].

#### *Overview of Primary Cell Culture Models in Preclinical Research of Prostate and Bladder Cancer DOI: http://dx.doi.org/10.5772/intechopen.99493*

All models involved in the cancer research have pros and cons hence the cost duration, experimental design and data analysis in developing the anticancer drug should be considered for the selection of the model. It is necessary to choose more effective preclinical platforms to screen the antitumor compounds [18]. Practically *in-vitro* models of tumors will not only give primary screening of potential antitumor drugs but it also prevents drugs with insufficient antitumor activity from entering into preclinical animal testing [19]. This chapter reviews the main features of primary cancer cell cultures, provides an overview of the different methods for their selection and management, and summarizes the wide range of studies that can be performed with them to improve the understanding of prostate and bladder cancer preclinical treatment processes.
