Molecular Genetics

Infection with the human papillomavirus (HPV) is the most common sexually transmitted infection, and it is the main risk factor for cervical cancer in women. This virus can also increase the risk of developing anal and penile cancer in men. HPV infection can also contribute to a small percentage of oral and throat cancers.

Human papillomavirus has multiple types, and they are classified based on their presence in clinical samples of cervical carcinoma. Determining different genotypes of HPV, including high-risk and probable high-risk, low-risk, and Unclassified types, is highly effective in managing the risk in patients with cervical cancer. Following up on patients provides valuable information about the persistence of infection and the possibility of concurrent infections of multiple types.

Typing the HPV virus using molecular methods has several significant effects on disease control:

• According to research, infection with High-Risk types is associated with an increased risk of cervical cancer.
• Identifying high-risk types and co-infections is vital for preventing the development of critical cancers.
•  Types 16 and 18 are responsible for approximately 25 to 30 percent of cervical cancers, while other high-risk types are also contributing factors.
•  Vaccination can only prevent cervical cancer caused by types 16 and 18, and it does not confer immunity against infections with other high-risk types.
•  Early identification and treatment in men can play a role in breaking the epidemiological
• cycle of infection.

Interpretation:

– HPV types can be divided into two groups based on their potential to cause malignant diseases in the reproductive system:

– High-risk includes: 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68

– Low-risk includes: 6, 11, 42, 43, and 44.

Since the advent of molecular methods, the Sanger sequencing method has been the most common technique for determining DNA sequences. However, despite its widespread applications, Sanger sequencing has several limitations, such as being time-consuming and costly. In recent years, significant advances have been made in DNA sequencing, leading to the development of innovative methods known as Next Generation Sequencing (NGS). These new approaches enable the high-throughput sequencing of a large portion of the genome with high accuracy, at a reduced cost, and in a significantly shorter time. As a result, NGS has gained a special place in the diagnosis of genetic diseases, allowing for the detection of genetic variations that were previously challenging to identify.

The genetic data stored in the form of DNA within the nuclei of various cells controls and regulates all human traits. DNA controls these traits and functions by encoding different proteins. The segments of DNA responsible for encoding proteins are called genes. It is estimated that humans have approximately 25,000 genes, but the functions of all these genes are not yet fully understood. Any change in the genetic material is termed a mutation, and mutations in any of these genes can lead to functional impairments and genetic diseases. To understand the functions of these genes in genetics, one approach is to investigate which genes undergo mutations and impairments in different diseases. So far, approximately 7,000 genes have been linked to various diseases. Each gene is composed of subunits called exons, and the collection of exons in an organism is referred to as the exome. Sequencing all these exons and genes makes it possible to rapidly identify all the positions where mutations have occurred. Complete Exome Sequencing offers the possibility of sequencing all these genes quickly and simultaneously identifying all the locations of mutations. This test is used when clinical symptoms do not lead to a clear diagnosis or when a suspected disease involves many known genes.