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What’s CD1 Got To Do With It?

CD1, or cyclin D1, is a protein that is involved with cell development and growth. All cells grow and divide, as older or diseased cells are replaced with new cells. However, cancerous cells divide uncontrollably, creating more and more cancer cells. In blood cancers, the rapid growth of cancer cells can crowd out healthy blood cells, including red blood cells, white blood cells, and platelets.

Mutations can cause too much CD1

Cancers develop when mutations occur in the DNA of the cell. Mutations may be inherited (passed from parent to child), influenced by environmental factors, or they can occur spontaneously during normal cell replication. Many cancers have mutations which cause the cell to produce an excess of CD1.

In one rare form of non-Hodgkin lymphoma, called mantle cell lymphoma (MCL), a common mutation occurs between chromosomes 11 and 14. Pieces of these two chromosomes switch and reattach to the other chromosome, called a translocation. This mutation is referred to as t(11;14) and causes an overproduction of the protein CD1. With this excess protein, the cancer cell begins to replicate more quickly and leads to an abundance of MCL cells.1

The translocation between chromosomes 11 and 14 is the most common mutation in MCL – found in about 85% of all cases – but other mutations can also cause too much CD1. There are also other proteins, like cyclin D2 and cyclin D3, which have similar growth effects on cells. Mutations that cause an excess of these proteins can also lead to cancer growth.1

Other cancers that have been found to have an overproduction of CD1 include lung cancer, breast cancer, and bladder cancer.2,3

Can we target CD1?

With the understanding of cyclins and the locations where they bind in the cell, called cyclin-dependent kinases (CDK), researchers have been studying ways to target these characteristics to treat or prevent cancer. However, translating the knowledge of these proteins to a potential treatment has been challenging.4 The two most promising targets have been CDK4 and CDK6, two of the receptors where cyclins attach. Three CDK inhibitors have been approved by the U.S. Food and Drug Administration (FDA) for use in metastatic breast cancer.5 To date, there are no CDK inhibitors for blood cancer.

This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

  1. Mantle cell lymphoma facts. Leukemia & Lymphoma Society. Available at Accessed 10/11/18.
  2. Alao JP. The regulation of cyclin D1 degradation: roles in cancer development and the potential for therapeutic invention. Molecular Cancer. 2007;6:24. doi:10.1186/1476-4598-6-24.
  3. Raje N, Hideshima T, Vallet S, et al. Targeting cyclin D1 in the treatment of multiple myeloma: preclinical validation of a novel specific small molecule cyclin D1 inhibitor, P276-00. Blood. 2006;108:3454. Abstract.
  4. Asghar U, Witkiewicz AK, Turner NC, Knudsen ES. The history and future of targeting cyclin-dependent kinases in cancer therapy. Nature reviews Drug discovery. 2015;14(2):130-146. doi:10.1038/nrd4504.
  5. Seymour C. CDK 4/6 inhibitors continue to revolutionize ER+ breast cancer care. OncLive. Available at Accessed 10/11/18.


  • Daniel Malito moderator
    1 year ago

    @emilyd Thanks, Emily. The more information that’s out there, the better. Cancer, blood cancer, is so complicated when it comes to the different types, subtypes, and sub-sub-sub-sub types, and so-on. Great job! Keep on keepin’ on, DPM

  • Emily Downward moderator author
    1 year ago

    Thanks, Daniel! I find it encouraging that researchers are uncovering more of what makes each type grow, as each of these details identifies new targets for treatment. Hope you are doing well! Warmly, Emily

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