WHO WE ARE

Castle Biosciences, Inc. (sometimes referred to as the “Company,” “Castle,” “we,” “us” or “our”) is applying innovative diagnostics to inform disease management and improve patient outcomes. For the diseases that our portfolio of tests cover, we believe the traditional approach to developing a treatment plan for cancers and other diseases using clinical and pathology factors alone is inadequate and can be improved by incorporating the personalized information our diagnostic and prognostic (or risk stratification) tests provide.

MISSION, VISION AND VALUES

Vision and Foundational Strategy

Since our inception in 2008, it has been our vision to transform disease management by keeping people first: patients, clinicians, employees and investors. This foundational strategy remains the guidepost for the direction of our company and the basis of long-term value creation.

We have three strategic guideposts that create value for customers, patients and stockholders:

Exceptional Employees—We hire and keep the right people, by our commitment to doing the right thing for employees and nurturing our thriving culture.

Continuous Evolution & Improvement—We are an industry leader by challenging the status quo with deep scientific expertise, unique value insight and robust data development.

Customer & Solution Centric—We value best-in-class customer experience at all points along the testing journey, and we leverage multiple solutions for a single customer to provide a single source of high quality molecular diagnostic tests.

April 12, 2023

Letter from our Chief Executive Officer

DEAR FELLOW STOCKHOLDERS,

☒	No fee required.			”Our full-year 2022 revenue increased by 46% over 2021 to $137 million, significantly exceeding our initial 2022 revenue guidance of $115-120 million.”
☐			Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.

Letter from Our Independent Chair

TO MY FELLOW CASTLE STOCKHOLDERS,

	(1)	Title of each class of securities to which transaction applies:
”The Board values input from our stockholders and believes meaningful engagement helps the Board understand key issues of importance to better inform our decision-making process.”	(2)	Aggregate number of securities to which transaction applies:
			(3)			Per unit price or other underlying value of transaction computed pursuant to Exchange Act Rule 0-11 (set forth the amount on which the filing fee is calculated and state how it was determined):
			(4)			Proposed maximum aggregate value of transaction:
			(5)			Total fee paid:
☐			Fee paid previously with preliminary materials.
☐			Check box if any part of the fee is offset as provided by Exchange Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee was paid previously. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.
			(1)			Amount Previously Paid:
			(2)			Form, Schedule or Registration Statement No.:
			(3)			Filing Party:
			(4)			Date Filed:

Set forth below is considered to bebiographical information for the Class II and Class III directors, whose terms of office as a “routine” matter under the rules of the NYSE. Accordingly, if you hold your shares in street name and do not provide voting instructions to your broker, bank or other agent that holds your shares, your broker, bank or other agent has discretionary authority under NYSE rules to vote your shares on this proposal.

Proxy Summary

GOVERNANCE HIGHLIGHTS

Our Board is committed to building long-term stockholder value and maintaining sound corporate governance practices. Based on discussions with stockholders and corporate governance best practices, our Board adopted stock ownership guidelines and other governance policies in the first quarter of 2023 to align our corporate governance practices with market practices and investor expectations:

All of our directors are not available to us in time to file a Form 8-K within four business days after the Annual Meeting, we intend to file a Form 8-K to publish preliminary results and, within four business days after the final results are known to us, file an additional Form 8-K to publish the final results.

Proxy Summary

COMPENSATION HIGHLIGHTS

We endeavor to maintain sound executive compensation policies and practices consistent with our executive compensation philosophy. A key priority in 2022 was to gather and address stockholder feedback following our first Say-on-Pay proposal. Highlights of our compensation policy and practices are set forth below:

What We Do

What We Don’t Do

Proposal 1

Election of Directors

Class I Director Nominees for Election for a Three-Year Term Expiring at Castle’s 2026 Annual Meeting of Stockholders

Proposal 1 Election of Directors

				Miles D. Harrison He has served as a member of our board of directors since April 2020. From January 2016 through April 2021, Mr. Harrison served as the North American President and General Manager of Galderma Laboratories, L.P., a global dermatology company. During his tenure at Galderma, Galderma launched multiple brands and new indications across the company’s Prescription, Consumer and Aesthetic businesses. Mr. Harrison also served as Galderma’s Vice President and General Manager of the Consumer Business Unit from August 2014 until February 2016, where the first prescription to OTC switch in acne in more than 30 years was secured and successfully launched. Prior to Galderma, Mr. Harrison spent most of his career at Novartis International AG, a global healthcare company based in Switzerland. From June 1987 to February 2014, Mr. Harrison held multiple leadership positions of increasing responsibility at Novartis across the Consumer, Oncology and Pharmaceuticals businesses, most recently as Vice President and Head of Global Advocacy. Mr. Harrison holds a B.A. (Honors) Degree in Geography from Sheffield Hallam University in the United Kingdom and has worked in the United Kingdom, Europe, Middle East and Latin America, in addition to his U.S.-based roles. Our Nominating and Corporate Governance Committee and board of directors believe Mr. Harrison’s experience in dermatology and his strategic leadership skills as an executive in the pharmaceutical and consumer healthcare industry qualify him to serve on our board of directors.
				Tiffany P. Olson She has served as a member of our board of directors since May 2021. From July 2013 to October 2021, Ms. Olson served as President of Nuclear & Precision Health Solutions at Cardinal Health, Inc., a multinational health care services company. From 2011 to 2013, Ms. Olson served as President of NaviMed, a consulting firm focused exclusively on the healthcare industry. From 2009 to 2011, Ms. Olson served led Diagnostics at Eli Lilly and Company. From 2005 to 2008, Ms. Olson served as the CEO and President of Roche Diagnostics Corporation, where from 1997 to 2005 she held various roles of increasing responsibility. Ms. Olson currently serves on the boards of Langham Logistics, a privately held freight management company, The Education and Research Foundation for Nuclear Medicine and Molecular Imaging, and Telix Pharmaceuticals, a publicly traded biopharmaceutical company on the Australian Securities Exchange. Ms. Olson holds an MBA from the University of St. Thomas, St. Paul, Minnesota, and a Bachelor of Science, Business degree from the University of Minnesota. Our Nominating and Corporate Governance Committee and board of directors believe that Ms. Olson’s extensive experience in life science and her strategic leadership skills as an executive in the pharmaceutical, diagnostics and health services industry qualify her to serve on our board of directors.

Proposal 1 Election of Directors

Class II Directors Continuing in Office Until Castle’s 2024 Annual Meeting of Stockholders

				Mara G. Aspinall She has served as a member of our board of directors since February 2015. Ms. Aspinall has served as Managing Director of BlueStone Venture Partners, a life science-focused venture capital firm investing in diagnostics, devices and digital health companies, since December 2017. Since June 2014, Ms. Aspinall has served as the President and CEO of Health Catalysts Group, a consulting firm that focuses on growth of early-stage life science and technology companies. From September 2011 until June 2014, Ms. Aspinall served as the President and CEO of the Ventana Medical Systems and the Global Head of Roche Tissue Diagnostics, a global leader in the development and commercialization of tissue-based cancer diagnostics. Prior to 2011, Ms. Aspinall served as President of Genzyme Pharmaceuticals and Genzyme Genetics. Ms. Aspinall currently serves as a director of OraSure Technologies, Inc., a publicly traded medical device manufacturer; Abcam, a publicly traded life sciences tools company; DA32 Life Science Tech Acquisition Corp., a public special purpose acquisition corporation focused on funding life science technologies; along with other privately held healthcare technology and medical insurance companies. Ms. Aspinall holds a B.A. degree in International Relations from Tufts University and an MBA from Harvard Business School. Ms. Aspinall is also certified in Cybersecurity Oversight from Carnegie Mellon University. Our Nominating and Corporate Governance Committee and board of directors believe that Ms. Aspinall’s operational expertise, international experience, diagnostics industry and cybersecurity knowledge qualify her to serve on our board of directors.
				Daniel M. Bradbury He has served as a member of our board of directors since September 2012, and as chair of our board of directors since September 2014. Since January 2020, Mr. Bradbury has served as Executive Chairman of Equillium, Inc., a publicly traded biotechnology company, that he co-founded and also served as its CEO from June 2018 until December 2019 and President from March 2017 until June 2018. Mr. Bradbury is the founder of, and has served as the managing member of, BioBrit, LLC, a life sciences consulting and investment firm, since September 2012. Mr. Bradbury served as President, CEO and a director of Amylin Pharmaceuticals, Inc. from March 2007 until Amylin’s acquisition by Bristol-Myers Squibb Company in August 2012. Prior to Amylin, Mr. Bradbury worked in marketing and sales for ten years at SmithKline Beecham Pharmaceuticals. Mr. Bradbury serves on the board of privately held companies and two publicly traded companies, Equillium, Inc. and Intercept Pharmaceuticals, Inc., each a biopharmaceutical company. He previously served on the board of directors of the following publicly traded companies: Corcept Therapeutics, Inc., a pharmaceutical company, from 2012 to 2019; Biocon Limited, a biotechnology company, from 2013 to 2022 and Geron Corporation, a biotechnology company, from 2012 to 2019; and Illumina, Inc., a biotechnology company, from 2004 to 2017. Mr. Bradbury holds a Bachelor of Pharmacy from Nottingham University and a Diploma in Management Studies from Harrow and Ealing Colleges of Higher Education in the United Kingdom. Our Nominating and Corporate Governance Committee and board of directors believe that Mr. Bradbury’s extensive experience as a life sciences executive and his other executive and boards of directors experience qualify him to serve on our board of directors.

Proposal 1 Election of Directors

Class III Directors Continuing in Office Until Castle’s 2025 Annual Meeting of Stockholders

Proposal 1 Election of Directors

Information Regarding the Board of Directors and Corporate Governance

COMPOSITION OF THE BOARD OF DIRECTORS

Castle’s board of directors is divided into three classes. Each class consists, as nearly as possible, of one-third of the total number of directors, and each class has a three-year term. Vacancies on the board of directors, including newly created directorships, may be filled only by persons elected by a majority of directors then in office. A director elected by the board of directors to fill a vacancy in a class, including vacancies created by an increase in the number of directors, shall serve for the remainder of the full term of that class until the director’s successor is duly elected and qualified.

Information Regarding the Board of Directors and Corporate Governance

We believe that the backgrounds and qualifications of our directors, considered as a group, should consist of a significant composite mix of experience, knowledge and abilities that will allow the Board to fulfill its responsibilities and should represent an appropriate balance between institutional knowledge and fresh perspectives.

BOARD STRUCTURE

The Board believes there is no single approach to corporate governance that is appropriate for all companies, and the key consideration in determining whether to implement a particular governance practice is whether that practice promotes the interests of stockholders, taking into account a company’s specific circumstances. The Board has reviewed the rationale for its current classified structure and continues to believe that a classified board is the appropriate board structure for Castle at this time and is in the best interest of our stockholders for the reasons set forth below:

In summary, we believe the Company has benefited from the independence and continuity of experienced leadership provided by our Board under its classified structure. We will continue afterto assess our Board’s structure, consider stockholder feedback and make changes when appropriate.

BOARD DIVERSITY

Our Board considers diversity, including gender and ethnic diversity, as adding to the Annual Meeting. This includes information regarding each director’s experience, qualifications, attributes or skills that led our boardoverall mix of directors to recommend them for service on our board of directors.

Information Regarding the National AssociationBoard of Corporate Directors and Carnegie Mellon University.

Information Regarding the Board of Directors and Corporate Governance

whether such risks and consequences as may be mitigated by any other compensation policies and practices, are reasonably likely to have a material adverse effect on the Company. While our board of directors oversees our risk management, management is responsible for day-to-day risk management processes. Our board of directors expects management to consider risk and risk management in each business decision, to proactively develop and monitor risk management strategies and processes for day-to-day activities and to effectively implement risk management strategies adopted by the Audit Committee and our board of directors. We believe this division of responsibilities is the most effective approach for addressing the risks we face and that our board of directors’ leadership structure, which also emphasizes the independence of our board of directors in its oversight of its business and affairs, supports this approach.

Information Regarding the performance, independenceBoard of Directors and qualifications of our independent auditors and determining whether to retain our existing independent auditors or engage new independent auditors;

Information Regarding the Board of Directors and Corporate Governance

Compensation Committee

Information Regarding the Board of Directors and Corporate Governance

necessary or appropriate in the performance of its duties. The Compensation Committee has direct responsibility for the oversight of the work of any advisers engaged for the purpose of advising the compensation committee.Compensation Committee. In particular, the Compensation Committee has the sole authority to retain compensation

Information Regarding the Board of Directors and Corporate Governance Committee and the Nominating and Corporate Governance Committee Charter.

Information Regarding the Board of Directors and Corporate Governance

Mr. Maetzold, our President and CEO, is also a member of our board of directors but did not receive any additional compensation for his service as a director. See the section titled “Compensation Discussion and Analysis—Elements of Our Executive Compensation Program” below for more information regarding the compensation earned by Mr. Maetzold.

We have reimbursed and will continue to reimburse all of our non-employee directors for their travel, lodging and other reasonable expenses incurred in attending meetings of our board of directors and committees of our board of directors.

Non-Employee Director Compensation Policy

Our board of directors has adopted a non-employee director compensation policy that is applicable to each member of our board of directors who is not also serving as an employee or consultant. Our Compensation Committee reviews non-employee director compensation levels annually and submits recommendations with respect to any changes in non-employee director compensation levels to our Board. In 2022, our Compensation Committee’s independent compensation consultant reviewed the market competitiveness of our non-employee director compensation policy relative to our compensation peer group and recommended certain changes based on governance best practices and market trends to ensure we can attract and retain a highly qualified board of directors.

Upon recommendation of the Compensation Committee, our Board approved an amendment to our non-employee director compensation policy in January 2023 that provided for the following compensation for service on our board of directors:

Cash Compensation

Equity Compensation

Prior to the January 2023 amendment, the initial grant was calculated as the number of stock option equivalent shares equal to the aggregate value of the initial grants, based on a Black-Scholes valuation methodology using an assumed stock price equal to the average of the closing prices of our common stock for each trading day within the 30 calendar days prior to the grant date. The total number of total stock option equivalent shares was then allocated as follows: (i) 67% to the grant of stock options and (ii) 33%, divided by two, to the grant of RSUs, in each case subject to certain rounding conventions.

Prior to the amendment, the total number of shares subject to the annual equity grants was calculated as the number of stock option equivalent shares equal to the aggregate value of the annual grants, based on a Black-Scholes valuation methodology and assumed stock price equal to the average of the closing prices of our common stock for each trading day within the 30 calendar days prior to the grant date. The total number of stock option equivalent shares was then allocated as follows: (i) 50% to the grant of stock options and (ii) 50%, divided by two, to the annual grant of RSUs, in each subject to certain rounding conventions. The shares subject to the annual grant through both stock options and RSUs will vest in full on the one-year anniversary of the date of grant.

In making the decision to allocate grants between stock option and RSUs, the Compensation Committee has continued to monitor the market trends and the investor preference for the Board to be aligned long-term with stockholder value creation. The Board believes that options provide a long-term time horizon reflective of development cycles for our business, while the RSUs provide compensation for current service and reinforce the ownership culture that we have built.

Information Regarding the Board of Directors and Corporate Governance

Each of the option or RSU grants described above were, or will be, granted under the 2019 Plan. Each such option or RSU grant will vest subject to the director’s continuous service to us, provided that each option or RSU will vest in full upon a change in control (as defined in the 2019 Plan). The term of each option is 10 years, subject to earlier termination as provided in the 2019 Plan, provided that upon a termination of service other than for death, disability or cause, the post-termination exercise period will be three months from the date of termination. An eligible director may decline all or any portion of his or her compensation by giving notice to us prior to the date cash may be paid or equity awards are to be granted, as the case may be.

STOCK OWNERSHIP GUIDELINES

The board of directors has adopted Stock Ownership Guidelines that apply to our CEO and our Section 16 officers and our non-employee directors. See the“—Stock Ownership Guidelines” section in the “Compensation Discussion and Analysis” section of this Proxy Statement for more information.

ENVIRONMENTAL, SOCIAL AND GOVERNANCE PROGRAM

We believe that building a strong ESG program that is relevant to our core business and our stakeholders is essential for success and were pleased to release our inaugural ESG report in November 2021. The release of this report marked an important milestone in our journey as a company and reinforced our commitment to serving our stakeholders in an ethical and responsible manner and to our vision of transforming disease management by keeping people first: patients, clinicians, employees and stockholders.

ESG Board Oversight

In April 2021, our Board amended our Audit Committee Charter to delegate the review and oversight of our ESG program to the Audit Committee, which was driven by our desire to integrate ESG principles into our business strategy in ways that optimize opportunities to make positive impacts while advancing long-term goals. We are committed to advancing our ESG strategy, improving our capabilities and measuring our progress based on key performance indicators.

In addition, we established an internal management committee, which is responsible for leading our ESG strategy and monitoring our initiatives. This internal ESG working group is led by a cross-functional team of leaders, including leaders from marketing, finance, human resources and operations.

Information Regarding the Board of Directors and Corporate Governance

2022 Highlights

As part of our 2022 ESG efforts, we prioritized assessing our Scope 1 and 2 GHG emissions; established a diversity, equity and inclusion statement; and developed a code of conduct for our vendors. Our senior leadership team is tasked with driving results in these areas, given the strategic importance of ESG. Against this backdrop, we have engaged with our internal and external stakeholders on various ESG topics to help further inform our future direction and priorities. Our 2022 areas of focus for various ESG initiatives included: (1) Culture of Inclusion, (2) Environmental Impact, and (3) Strong Governance.

Culture of Inclusion

We thrive on the contributions each person brings to Castle by valuing diversity, developing talent, fostering teamwork and rewarding success. We understand the importance of maintaining a strong corporate culture with our employees at the center, based on the cornerstones we laid in 2008 at our inception: trust, excellence, collaboration, integrity, innovation and excitement. To foster these values and to attract and retain quality employees, we strive to hire, develop and promote a workforce that shares our mission and cultivates a culture of inclusion.

Diversity, Equity and Inclusion

Castle’s DEI strategy is focused on creating a culture of belonging, where employees can be their authentic selves. Our commitment to DEI starts with our goal of developing a workforce that is diverse in background, knowledge, skill and experience.

Information Regarding the Board of Directors and Corporate Governance

As of December 31, 2022, our overall workforce was 66% female and 26% ethnically or racially diverse (as self-reported by the employee or, in cases where the employee did not provide this information, as determined by us). Additionally, half of our board of directors is female, which we believe exemplifies our commitment to diversity of opinion and perspectives, starting at the board level. In 2022, we developed our DEI Statement. We have implemented policies and training focused on non-discrimination and harassment prevention. Other notable highlights include:

We recognize that Castle plays an important part in the lives of our employees and strive to create a transparent workplace where employees feel heard, valued and appreciated for who they are. We encourage every one of our team members to form deeper relationships with those around them. In 2022, we conducted employee surveys and 81% of our employees indicated that they are “engaged” or “enthusiastically engaged” in the culture at Castle compared to the healthcare benchmark of 53% for this survey (the healthcare benchmark average of 53% is for other healthcare companies who conducted the same employee engagement survey in 2022).

Human Capital Management

As a rapidly growing company, we have begun to transform and modernize our culture and talent management by implementing Human Capital Management (“HCM”) reporting and practices to establish a foundation to enable leaders to better hire talent and manage teams. These practices include standards for setting goals, performance evaluations, succession planning, and learning and development.

The health and safety of our employees is paramount, and our success is fundamentally connected with the well-being of our people. Thus, the health and well-being of our employees is our top priority and in recognition of this, we aim to provide a robust health and wellness package, including:

Social Responsibility

We are committed to improving health through innovative tests that help guide patient care, which includes our efforts to make our tests more accessible and more affordable, and we engage with organizations who share these goals.

We believe that quality care should not be dependent on a patient’s financial situation. We work with a variety of insurance providers to obtain payment for our tests, including Medicare, Medicaid, commercial insurers and the United States Department of Veterans Affairs. We also offer financial support through our Patient Assistance Program.

We also believe that investing in local communities to create social outcomes is at the heart of generating our culture of inclusion, and we believe in giving back to the communities in which we live and work. Patient advocacy is at the center of our community engagement strategy. We are proud to work alongside some of the leading skin cancer, esophageal cancer, mental health and ocular cancer organizations through fundraising efforts, educational sponsorship, community development efforts, charity drives, and partnerships targeted at patient groups who may benefit from our tests.

Information Regarding the Board of Directors and Corporate Governance

Environmental Impact

We are committed to responsible environmental practices that include conservation of natural resources, pollution prevention, and reduction of waste. We embed the principles of advancing a circular economy into our practices. We are devoted to operating our business in a sustainable manner and have undertaken several initiatives designed to reduce our impact on the environment and to promote environmentally friendly projects and practices. In 2022, we: