What is the Difference Between HPV 16 and 18

The key difference between HPV 16 and 18 is that HPV 16 is a strain of the human papillomavirus that is responsible for 50 % of cervical cancers in humans, while HPV 18 is a strain of the human papillomavirus that is responsible for 20 % of cervical cancers in humans.

Human papillomavirus (HPV) causes sexually transmitted infections (STIs). Currently, there are more than 150 types or strains of HPV. Low-risk strains can’t cause cervical cancer and are normally treatable. High-risk strains can cause abnormal cells to form on the cervix, which develops into cervical cancers if left untreated. These high-risk strains can also cause other cancers. HPV strains are normally responsible for different cancers in humans. Specifically, they are the causative agent of cervical cancers in women. Low-risk strains may include HPV6 and HPV11, while high-risk strains may include HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68. Among these strains, HPV16 and HPV18 are responsible for most HPV-related cancers.

1. Overview and Key Difference
2. What is HPV 16
3. What is HPV 18
4. Similarities – HPV 16 and 18
5. HPV 16 vs. 18 in Tabular Form
6. Summary – HPV 16 vs. 18

What is HPV 16?

HPV 16 is a strain of the human papillomavirus that is responsible for 50% of cervical cancers in humans. HPV16 and HPV18, together, account for 70% of cases of cervical cancer in women. It also causes other types of cancers. HPV 16 is strongly associated with anal cancer and throat cancer. HPV16 is responsible for almost 90% of HPV-positive oropharyngeal cancers. Moreover, HPV16 is identified as a causative agent for developing genital cancer and mouth cancer as well.

Figure 01: HPV 16

Papillomaviruses contain a double-stranded, circular DNA genome of approximately 8 kb in size. HPV 16 strain genome size is around 7906 bp. It has an upstream regulatory region (URR) of 853 bp. Furthermore, it consists of 8 protein-coding genes (L1, L2, E1, E2, E4, E5, E6, and E7) and 2 noncoding regions called the noncoding region (NCR) and the long control region (LCR).

What is HPV 18?

HPV 18 is a strain of the human papillomavirus that is responsible for 20% of cervical cancers in humans. The genome size of this strain is 7857 bp. It has an upstream regulatory region (URR) of 825 bp as well. Moreover, it contains early expressed genes (E1, E2, E4, E5, E6, and E7), late genes (L1, L2) and a long control region.

Figure 02: Cervical Cancer

In addition, HPV 18 is also responsible for the development of anal dysplasia and genital cancers. Furthermore, the nonavalent vaccine known as Gardasil 9 provides protection against HPV strains such as 6, 11, 16, 18, 31, 33, 45, 52, and 58.

What are the Similarities Between HPV 16 and 18?

HPV16 and HPV18 are two high-risk HPV strains.
They are responsible for most HPV-related cancers.
Together, HPV16 and HPV18 account for 70% of cases of cervical cancer in women.
Both strains have genes such as L1, L2, E1, E2, E4, E5, E6, and E7.
The nonavalent vaccine known as Gardasil 9 provides protection against HPV 16 and 18.

What is the Difference Between HPV 16 and 18?

HPV 16 is a strain of the human papillomavirus that is responsible for 50% of cervical cancers in humans, while HPV 18 is a strain of the human papillomavirus that is responsible for 20% of cervical cancers in humans. Thus, this is the key difference between HPV16 and HPV18. Furthermore, HPV 16 is the most common high-risk type of HPV strain, while HPV18 is a less common high-risk type of HPV strain.

The infographic below presents the differences between HPV16 and HPV18 in tabular form for side-by-side comparison.

Summary – HPV 16 vs. 18

There are different low-risk and high-risk strains of human papillomavirus. HPV16 and HPV18 are two high-risk HPV strains. HPV 16 is the most common high-risk type of HPV strain, while HPV18 is a less common high-risk type of HPV strain. Moreover, HPV 16 is responsible for 50% of cervical cancers in women, whereas HPV 18 is responsible for 20% of cervical cancers in women. So, this is the summary of the difference between HPV 16 and 18.

Reference:

1. “Information about Human Papillomavirus (HPV).” WebMD.
2. “Human Papillomavirus Type 18.” ScienceDirect Topics.

Image Courtesy:

1. “HPV-16 genome organization” By Xmort – en: wiki (CC BY-SA 4.0) via Commons Wikimedia
2. “Cervical-cancer” By Lolaia – Own work (CC BY-SA 4.0) via Commons Wikimedia