# EDGAR Filing Document

**Accession Number:** 0001447362
**File Stem:** 0001447362-23-000039
**Filing Date:** 2023-2
**Character Count:** 40057
**Document Hash:** a75f4264662db8c658bf6d169e944eb7
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001447362-23-000039.hdr.sgml**: 20230228

**ACCESSION NUMBER**: 0001447362-23-000039

**CONFORMED SUBMISSION TYPE**: S-8

**PUBLIC DOCUMENT COUNT**: 5

**FILED AS OF DATE**: 20230228

**DATE AS OF CHANGE**: 20230228

**EFFECTIVENESS DATE**: 20230228

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** CASTLE BIOSCIENCES INC
- **CENTRAL INDEX KEY:** 0001447362
- **STANDARD INDUSTRIAL CLASSIFICATION:** SERVICES-MEDICAL LABORATORIES [8071]
- **IRS NUMBER:** 770701774
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** S-8
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-270141
- **FILM NUMBER:** 23687519

**BUSINESS ADDRESS:**
- **STREET 1:** 505 S FRIENDSWOOD DRIVE
- **STREET 2:** SUITE 401
- **CITY:** FRIENDSWOOD
- **STATE:** TX
- **ZIP:** 77546
- **BUSINESS PHONE:** 866-788-9007

**MAIL ADDRESS:**
- **STREET 1:** 505 S FRIENDSWOOD DRIVE
- **STREET 2:** SUITE 401
- **CITY:** FRIENDSWOOD
- **STATE:** TX
- **ZIP:** 77546

**As filed with the Securities and Exchange Commission on February 28, 2023** 

**Registration No. 333-** 

**UNITED STATES** 

**SECURITIES AND EXCHANGE COMMISSION** 

**Washington, D.C. 20549** 

**FORM S-8** 

**REGISTRATION STATEMENT** 

***UNDER***

***THE SECURITIES ACT OF 1933***

**Castle Biosciences, Inc.** 

**(Exact name of registrant as specified in its charter)** 

---

| | |
|:---|:---|
| **Delaware** | **77-0701774** |
| **(State or other jurisdiction of**<br>**incorporation or organization)** | **(I.R.S. Employer**<br>**Identification No.)** |
| **505 S. Friendswood Drive, Suite 401**<br>**Friendswood, Texas** | **77546** |
| **(Address of Principal Executive Offices)** | **(Zip Code)** |

---

<br>**Castle Biosciences, Inc. 2019 Equity Incentive Plan**

**Castle Biosciences, Inc. 2019 Employee Stock Purchase Plan** 

**(Full titles of the plans)** 

**Derek J. Maetzold** 

**President and Chief Executive Officer** 

**Castle Biosciences, Inc.** 

**505 S. Friendswood Drive, Suite 401** 

**Friendswood, Texas 77546** 

**(866) 788-9907** 

**(Name, address, including zip code, and telephone number, including area code, of agent for service)** 

***Copies to:***

**Thomas A. Coll, Esq.**<br>**Karen E. Deschaine, Esq.**<br>**Cooley LLP**<br>**10265 Science Center Drive**<br>**San Diego, California 92121**<br>**(858) 550-6000**<br>

Indicate by check mark whether the Registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.

---

| | | | |
|:---|:---|:---|:---|
| Large accelerated filer | □ | Accelerated filer | □ |
| Non-accelerated filer | ⌧ | Smaller reporting company | ⌧ |
| Emerging growth company | □ | | |

---

------

If an emerging growth company, indicate by check mark if the Registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. □

------

**EXPLANATORY NOTE**

This Registration Statement on Form S-8 is being filed by Castle Biosciences, Inc. (the "***Registrant***") for the purpose of registering (i) an additional 1,327,684 shares of the Registrant's Common Stock, $0.001 par value per share ("***Common Stock***"), under the Registrant's 2019 Equity Incentive Plan (the "***2019 Plan***"), pursuant to the provisions of the 2019 Plan providing for an automatic increase in the number of shares of Common Stock reserved and available for issuance under the 2019 Plan, and (ii) 265,536 additional shares of Common Stock under the Registrant's 2019 Employee Stock Purchase Plan (the "***2019 ESPP***") pursuant to the provisions of the 2019 ESPP providing for an automatic increase in the number of shares of Common Stock reserved and available for issuance under the 2019 ESPP, in each case on January 1, 2023.

**INCORPORATION OF DOCUMENTS BY REFERENCE** 

This Registration Statement is being filed for the purpose of registering additional securities of the same class as other securities for which Registration Statements of the Registrant on Form S-8 relating to the same employee benefit plans are effective.

The Registrant previously registered shares of its Common Stock for issuance under the 2019 Plan and 2019 ESPP under Registration Statements on Form S-8 filed with the Securities and Exchange Commission (the "***SEC***") on <u>[July 29, 2019 (File No. 333-232884)](http://www.sec.gov/Archives/edgar/data/1447362/000114036119013647/nt10003552x1_s8.htm)</u>, <u>[March 10, 2020 (File No. 333-237062)](http://www.sec.gov/Archives/edgar/data/1447362/000144736220000030/forms-8x2019equityincentiv.htm)</u>, <u>[March 11, 2021 (File No. 333-254179)](https://www.sec.gov/Archives/edgar/data/1447362/000144736221000049/forms-8x2019equityincentiv.htm)</u> and <u>[February 28, 2022 (File No. 333-263094)](https://www.sec.gov/Archives/edgar/data/1447362/000144736222000046/forms-8x2019equityincentiv.htm)</u>. Pursuant to General Instruction E to Form S-8, this Registration Statement hereby incorporates by reference the contents of the Registration Statements referenced above.

**ITEM 8. EXHIBITS.** 

---

| | |
|:---|:---|
| **Exhibit Number** | &nbsp;&nbsp;**Description** |
| 4.1 | <u>[Amended and Restated Certificate of Incorporation of the Registrant, incorporated by reference to Exhibit 3.1 to the Registrant's Current Report on Form 8-K, filed with the SEC on July 29, 2019.](http://www.sec.gov/Archives/edgar/data/1447362/000114036119013617/nc10003561x1_ex3-1.htm)</u> |
| 4.2 | <u>[Amended and Restated Bylaws of the Registrant, incorporated by reference to Exhibit 3.2 to the Registrant's Current Report on Form 8-K, filed with the SEC on July 29, 2019.](https://www.sec.gov/Archives/edgar/data/1447362/000114036119013617/nc10003561x1_ex3-2.htm)</u> |
| 4.3 | <u>[Form of Common Stock Certificate of the Registrant. incorporated by reference to Exhibit 4.1 to the Registrant's Registration Statement on Form S-1 (File No. 333-232369), originally filed with the SEC on June 26, 2019, as amended.](https://www.sec.gov/Archives/edgar/data/1447362/000114036119012901/nt10000802x4_ex4-1.htm)</u> |
| 5.1\* | <u>[Opinion of Cooley LLP.](exhibit51-opinionofcooleyf.htm)</u> |
| 23.1\* | <u>[Consent of KPMG LLP, Independent Registered Public Accounting Firm.](ex231-kpmgsx8opinionfebrua.htm)</u> |
| 23.2\* | <u>[Consent of Cooley LLP. Reference is made to Exhibit 5.1.](exhibit51-opinionofcooleyf.htm)</u> |
| 24.1\* | <u>[Power of Attorney. Reference is made to the signature page hereto.](#ib29d124278dd432ea7071aca7117ed8f_4)</u> |
| 99.1 | <u>[Castle Biosciences, Inc. 2019 Equity Incentive Plan, incorporated by reference to Exhibit 99.3 to the Registrant's Registration Statement on Form S-8 (File No. 333-232884), filed with the SEC on July 29, 2019.](https://www.sec.gov/Archives/edgar/data/1447362/000114036119013647/nt10003552x1_ex99-3.htm)</u> |
| 99.2 | <u>[Forms of Stock Option Grant Notice, Option Agreement and Notice of Exercise under the 2019 Plan, incorporated by reference to Exhibit 10.7 to the Registrant's Registration Statement on Form S-1 (File No. 333-232369), originally filed with the SEC on June 26, 2019, as amended.](https://www.sec.gov/Archives/edgar/data/1447362/000114036119011686/nt10000802x2_ex10-7.htm)</u> |
| 99.3 | <u>[Forms of Restricted Stock Unit Grant Notice and Restricted Stock Unit Award Agreement under the 2019 Equity Incentive Plan, incorporated by reference to Exhibit 10.1 to the Registrant's Quarterly Report on Form 10-Q, filed with SEC on November 9, 2020.](https://www.sec.gov/Archives/edgar/data/1447362/000144736220000257/exhibit101-q32020.htm)</u> |
| 99.4 | <u>[Castle Biosciences, Inc. 2019 Employee Stock Purchase Plan, incorporated by reference to Exhibit 10.8 to the Registrant's Registration Statement on Form S-1 (File No. 333-232369), originally filed with the SEC on June 26, 2019, as amended.](https://www.sec.gov/Archives/edgar/data/1447362/000114036119012901/nt10000802x4_ex10-8.htm)</u> |
| 107\* | <u>[Filing Fee Table](ex107-filingfees2023.htm)</u> |

---

__________________________________

\*&nbsp;&nbsp;&nbsp;&nbsp;Filed herewith.

------

**SIGNATURES**

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Friendswood, State of Texas, on February 28, 2023.

---

| | |
|:---|:---|
| **CASTLE BIOSCIENCES, INC.** | **CASTLE BIOSCIENCES, INC.** |
| By: | /s/ Derek J. Maetzold |
|  | Derek J. Maetzold |
|  | *President and Chief Executive Officer* |

---

**POWER OF ATTORNEY** 

KNOW ALL BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Derek J. Maetzold and Frank Stokes, and each of them, as his or her true and lawful attorneys-in-fact and agents, each with the full power of substitution, for him or her and in his or her name, place or stead, in any and all capacities, to sign any and all amendments to this Registration Statement (including post-effective amendments), and to file the same, with exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or their substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated.

------

---

| | | |
|:---|:---|:---|
| **Signature** | **Title** | **Date** |
| /s/ Derek J. Maetzold | President, Chief Executive Officer and<br>Director | February 28, 2023 |
| Derek J. Maetzold | *(Principal Executive Officer)* |  |
| /s/ Frank Stokes | Chief Financial Officer | February 28, 2023 |
| Frank Stokes | *(Principal Financial and Accounting Officer)* |  |
| /s/ Daniel M. Bradbury | Chairperson of the Board of Directors | February 28, 2023 |
| Daniel M. Bradbury |  |  |
| /s/ Mara G. Aspinall | Member of the Board of Directors | February 28, 2023 |
| Mara G. Aspinall |  |  |
| /s/ Kimberlee S. Caple | Member of the Board of Directors | February 28, 2023 |
| Kimberlee S. Caple |  |  |
| /s/ G. Bradley Cole | Member of the Board of Directors | February 28, 2023 |
| G. Bradley Cole |  |  |
| /s/ Ellen Goldberg | Member of the Board of Directors | February 28, 2023 |
| Ellen Goldberg |  |  |
| /s/ Miles D. Harrison | Member of the Board of Directors | February 28, 2023 |
| Miles D. Harrison |  |  |
| /s/ Tiffany P. Olson | Member of the Board of Directors | February 28, 2023 |
| Tiffany P. Olson |  |  |

---

## Ex-Filing

**Exhibit 107**

**Calculation of Filing Fee Table**

**Form S-8**

(Form Type)

**Castle Biosciences, Inc.**

(Exact Name of Registrant as Specified in its Charter)

<u>Table 1: Newly Registered Securities</u>

---

| | | | | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|:---|:---|:---|
| **Security Type** | **Security Class Title** | **Fee Calculation Rule** | **Amount Registered**<sup>(1)</sup> | **Proposed Maximum Offering Price Per Unit**<sup>(2)</sup> | **Proposed Maximum Offering Price Per Unit**<sup>(2)</sup> | **Maximum Aggregate Offering Price** | **Maximum Aggregate Offering Price** | **Fee Rate** | **Amount of Registration Fee** | **Amount of Registration Fee** |
| Equity | **2019 Equity Incentive Plan**<br>Common Stock, par value $0.001 per share | Other | 1327684<sup>(3)</sup> | $| 23.58 | $| 31306788.72 | 0.0001102 | $| 3450.01 |
| Equity | **2019 Employee Stock Purchase Plan**<br>Common Stock, par value $0.001 per share | Other | 265536<sup>(4)</sup> | $| 23.58 | $| 6261338.88 | 0.0001102 | $| 690.00 |
| Total Offering Amounts |  |  |  |  |  | $| 37568127.60 |  | $| 4140.01 |
| Total Fee Offsets |  |  |  |  |  |  |  |  | $|  |
| Net Fee Due |  |  |  |  |  |  |  |  | $| 4140.01 |
| (1) | Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the "***Securities Act***"), this Registration Statement shall also cover any additional shares of Common Stock, par value $0.001 per share ("***Common Stock***"), of Castle Biosciences, Inc. (the "***Registrant***") that become issuable under the Registrant's 2019 Equity Incentive Plan (the "***2019 Plan***") or the Registrant's 2019 Employee Stock Purchase Plan (the "***2019 ESPP***") by reason of any stock dividend, stock split, recapitalization or other similar transaction.  | Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the "***Securities Act***"), this Registration Statement shall also cover any additional shares of Common Stock, par value $0.001 per share ("***Common Stock***"), of Castle Biosciences, Inc. (the "***Registrant***") that become issuable under the Registrant's 2019 Equity Incentive Plan (the "***2019 Plan***") or the Registrant's 2019 Employee Stock Purchase Plan (the "***2019 ESPP***") by reason of any stock dividend, stock split, recapitalization or other similar transaction.  | Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the "***Securities Act***"), this Registration Statement shall also cover any additional shares of Common Stock, par value $0.001 per share ("***Common Stock***"), of Castle Biosciences, Inc. (the "***Registrant***") that become issuable under the Registrant's 2019 Equity Incentive Plan (the "***2019 Plan***") or the Registrant's 2019 Employee Stock Purchase Plan (the "***2019 ESPP***") by reason of any stock dividend, stock split, recapitalization or other similar transaction.  | Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the "***Securities Act***"), this Registration Statement shall also cover any additional shares of Common Stock, par value $0.001 per share ("***Common Stock***"), of Castle Biosciences, Inc. (the "***Registrant***") that become issuable under the Registrant's 2019 Equity Incentive Plan (the "***2019 Plan***") or the Registrant's 2019 Employee Stock Purchase Plan (the "***2019 ESPP***") by reason of any stock dividend, stock split, recapitalization or other similar transaction.  | Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the "***Securities Act***"), this Registration Statement shall also cover any additional shares of Common Stock, par value $0.001 per share ("***Common Stock***"), of Castle Biosciences, Inc. (the "***Registrant***") that become issuable under the Registrant's 2019 Equity Incentive Plan (the "***2019 Plan***") or the Registrant's 2019 Employee Stock Purchase Plan (the "***2019 ESPP***") by reason of any stock dividend, stock split, recapitalization or other similar transaction.  | Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the "***Securities Act***"), this Registration Statement shall also cover any additional shares of Common Stock, par value $0.001 per share ("***Common Stock***"), of Castle Biosciences, Inc. (the "***Registrant***") that become issuable under the Registrant's 2019 Equity Incentive Plan (the "***2019 Plan***") or the Registrant's 2019 Employee Stock Purchase Plan (the "***2019 ESPP***") by reason of any stock dividend, stock split, recapitalization or other similar transaction.  | Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the "***Securities Act***"), this Registration Statement shall also cover any additional shares of Common Stock, par value $0.001 per share ("***Common Stock***"), of Castle Biosciences, Inc. (the "***Registrant***") that become issuable under the Registrant's 2019 Equity Incentive Plan (the "***2019 Plan***") or the Registrant's 2019 Employee Stock Purchase Plan (the "***2019 ESPP***") by reason of any stock dividend, stock split, recapitalization or other similar transaction.  | Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the "***Securities Act***"), this Registration Statement shall also cover any additional shares of Common Stock, par value $0.001 per share ("***Common Stock***"), of Castle Biosciences, Inc. (the "***Registrant***") that become issuable under the Registrant's 2019 Equity Incentive Plan (the "***2019 Plan***") or the Registrant's 2019 Employee Stock Purchase Plan (the "***2019 ESPP***") by reason of any stock dividend, stock split, recapitalization or other similar transaction.  | Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the "***Securities Act***"), this Registration Statement shall also cover any additional shares of Common Stock, par value $0.001 per share ("***Common Stock***"), of Castle Biosciences, Inc. (the "***Registrant***") that become issuable under the Registrant's 2019 Equity Incentive Plan (the "***2019 Plan***") or the Registrant's 2019 Employee Stock Purchase Plan (the "***2019 ESPP***") by reason of any stock dividend, stock split, recapitalization or other similar transaction.  | Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the "***Securities Act***"), this Registration Statement shall also cover any additional shares of Common Stock, par value $0.001 per share ("***Common Stock***"), of Castle Biosciences, Inc. (the "***Registrant***") that become issuable under the Registrant's 2019 Equity Incentive Plan (the "***2019 Plan***") or the Registrant's 2019 Employee Stock Purchase Plan (the "***2019 ESPP***") by reason of any stock dividend, stock split, recapitalization or other similar transaction.  |
| (2) | This estimate is made pursuant to Rule 457(h)(1) and Rule 457(c) of the Securities Act solely for purposes of calculating the registration fee. The price per share and aggregate offering price are based upon the average of the high and low prices of the Common Stock on February 22, 2023, as reported on the Nasdaq Global Market. | This estimate is made pursuant to Rule 457(h)(1) and Rule 457(c) of the Securities Act solely for purposes of calculating the registration fee. The price per share and aggregate offering price are based upon the average of the high and low prices of the Common Stock on February 22, 2023, as reported on the Nasdaq Global Market. | This estimate is made pursuant to Rule 457(h)(1) and Rule 457(c) of the Securities Act solely for purposes of calculating the registration fee. The price per share and aggregate offering price are based upon the average of the high and low prices of the Common Stock on February 22, 2023, as reported on the Nasdaq Global Market. | This estimate is made pursuant to Rule 457(h)(1) and Rule 457(c) of the Securities Act solely for purposes of calculating the registration fee. The price per share and aggregate offering price are based upon the average of the high and low prices of the Common Stock on February 22, 2023, as reported on the Nasdaq Global Market. | This estimate is made pursuant to Rule 457(h)(1) and Rule 457(c) of the Securities Act solely for purposes of calculating the registration fee. The price per share and aggregate offering price are based upon the average of the high and low prices of the Common Stock on February 22, 2023, as reported on the Nasdaq Global Market. | This estimate is made pursuant to Rule 457(h)(1) and Rule 457(c) of the Securities Act solely for purposes of calculating the registration fee. The price per share and aggregate offering price are based upon the average of the high and low prices of the Common Stock on February 22, 2023, as reported on the Nasdaq Global Market. | This estimate is made pursuant to Rule 457(h)(1) and Rule 457(c) of the Securities Act solely for purposes of calculating the registration fee. The price per share and aggregate offering price are based upon the average of the high and low prices of the Common Stock on February 22, 2023, as reported on the Nasdaq Global Market. | This estimate is made pursuant to Rule 457(h)(1) and Rule 457(c) of the Securities Act solely for purposes of calculating the registration fee. The price per share and aggregate offering price are based upon the average of the high and low prices of the Common Stock on February 22, 2023, as reported on the Nasdaq Global Market. | This estimate is made pursuant to Rule 457(h)(1) and Rule 457(c) of the Securities Act solely for purposes of calculating the registration fee. The price per share and aggregate offering price are based upon the average of the high and low prices of the Common Stock on February 22, 2023, as reported on the Nasdaq Global Market. | This estimate is made pursuant to Rule 457(h)(1) and Rule 457(c) of the Securities Act solely for purposes of calculating the registration fee. The price per share and aggregate offering price are based upon the average of the high and low prices of the Common Stock on February 22, 2023, as reported on the Nasdaq Global Market. |
| (3) | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 Plan on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 Plan. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 Plan will be automatically increased by an amount equal to the lesser of: (a) 5% of the total number of shares of capital stock of the Registrant outstanding on December 31 of the preceding calendar year; or (b) such lesser number of shares of Common Stock as the Registrant's board of directors (the "***Board***") may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 Plan on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 Plan. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 Plan will be automatically increased by an amount equal to the lesser of: (a) 5% of the total number of shares of capital stock of the Registrant outstanding on December 31 of the preceding calendar year; or (b) such lesser number of shares of Common Stock as the Registrant's board of directors (the "***Board***") may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 Plan on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 Plan. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 Plan will be automatically increased by an amount equal to the lesser of: (a) 5% of the total number of shares of capital stock of the Registrant outstanding on December 31 of the preceding calendar year; or (b) such lesser number of shares of Common Stock as the Registrant's board of directors (the "***Board***") may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 Plan on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 Plan. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 Plan will be automatically increased by an amount equal to the lesser of: (a) 5% of the total number of shares of capital stock of the Registrant outstanding on December 31 of the preceding calendar year; or (b) such lesser number of shares of Common Stock as the Registrant's board of directors (the "***Board***") may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 Plan on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 Plan. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 Plan will be automatically increased by an amount equal to the lesser of: (a) 5% of the total number of shares of capital stock of the Registrant outstanding on December 31 of the preceding calendar year; or (b) such lesser number of shares of Common Stock as the Registrant's board of directors (the "***Board***") may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 Plan on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 Plan. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 Plan will be automatically increased by an amount equal to the lesser of: (a) 5% of the total number of shares of capital stock of the Registrant outstanding on December 31 of the preceding calendar year; or (b) such lesser number of shares of Common Stock as the Registrant's board of directors (the "***Board***") may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 Plan on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 Plan. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 Plan will be automatically increased by an amount equal to the lesser of: (a) 5% of the total number of shares of capital stock of the Registrant outstanding on December 31 of the preceding calendar year; or (b) such lesser number of shares of Common Stock as the Registrant's board of directors (the "***Board***") may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 Plan on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 Plan. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 Plan will be automatically increased by an amount equal to the lesser of: (a) 5% of the total number of shares of capital stock of the Registrant outstanding on December 31 of the preceding calendar year; or (b) such lesser number of shares of Common Stock as the Registrant's board of directors (the "***Board***") may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 Plan on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 Plan. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 Plan will be automatically increased by an amount equal to the lesser of: (a) 5% of the total number of shares of capital stock of the Registrant outstanding on December 31 of the preceding calendar year; or (b) such lesser number of shares of Common Stock as the Registrant's board of directors (the "***Board***") may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 Plan on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 Plan. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 Plan will be automatically increased by an amount equal to the lesser of: (a) 5% of the total number of shares of capital stock of the Registrant outstanding on December 31 of the preceding calendar year; or (b) such lesser number of shares of Common Stock as the Registrant's board of directors (the "***Board***") may designate prior to the applicable January 1<sup>st</sup>.  |
| (4) | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 ESPP on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 ESPP. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 ESPP will be automatically increased by an amount equal to the lesser of: (a) 1% of the total number of shares of capital stock outstanding on December 31 of the preceding calendar year; (b) 411,935 shares; or (c) such lesser number of shares of Common Stock as the Board may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 ESPP on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 ESPP. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 ESPP will be automatically increased by an amount equal to the lesser of: (a) 1% of the total number of shares of capital stock outstanding on December 31 of the preceding calendar year; (b) 411,935 shares; or (c) such lesser number of shares of Common Stock as the Board may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 ESPP on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 ESPP. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 ESPP will be automatically increased by an amount equal to the lesser of: (a) 1% of the total number of shares of capital stock outstanding on December 31 of the preceding calendar year; (b) 411,935 shares; or (c) such lesser number of shares of Common Stock as the Board may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 ESPP on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 ESPP. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 ESPP will be automatically increased by an amount equal to the lesser of: (a) 1% of the total number of shares of capital stock outstanding on December 31 of the preceding calendar year; (b) 411,935 shares; or (c) such lesser number of shares of Common Stock as the Board may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 ESPP on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 ESPP. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 ESPP will be automatically increased by an amount equal to the lesser of: (a) 1% of the total number of shares of capital stock outstanding on December 31 of the preceding calendar year; (b) 411,935 shares; or (c) such lesser number of shares of Common Stock as the Board may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 ESPP on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 ESPP. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 ESPP will be automatically increased by an amount equal to the lesser of: (a) 1% of the total number of shares of capital stock outstanding on December 31 of the preceding calendar year; (b) 411,935 shares; or (c) such lesser number of shares of Common Stock as the Board may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 ESPP on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 ESPP. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 ESPP will be automatically increased by an amount equal to the lesser of: (a) 1% of the total number of shares of capital stock outstanding on December 31 of the preceding calendar year; (b) 411,935 shares; or (c) such lesser number of shares of Common Stock as the Board may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 ESPP on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 ESPP. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 ESPP will be automatically increased by an amount equal to the lesser of: (a) 1% of the total number of shares of capital stock outstanding on December 31 of the preceding calendar year; (b) 411,935 shares; or (c) such lesser number of shares of Common Stock as the Board may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 ESPP on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 ESPP. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 ESPP will be automatically increased by an amount equal to the lesser of: (a) 1% of the total number of shares of capital stock outstanding on December 31 of the preceding calendar year; (b) 411,935 shares; or (c) such lesser number of shares of Common Stock as the Board may designate prior to the applicable January 1<sup>st</sup>.  | Represents shares of Common Stock that were automatically added to the shares authorized for issuance under the 2019 ESPP on January 1, 2023 pursuant to an "evergreen" provision contained in the 2019 ESPP. Pursuant to such provision, on January 1<sup>st</sup> of each year through (and including) January 1, 2029, the number of shares authorized for issuance under the 2019 ESPP will be automatically increased by an amount equal to the lesser of: (a) 1% of the total number of shares of capital stock outstanding on December 31 of the preceding calendar year; (b) 411,935 shares; or (c) such lesser number of shares of Common Stock as the Board may designate prior to the applicable January 1<sup>st</sup>.  |

---

## Exhibit 5.1

**Exhibit 5.1**

![cooleylogo2a.jpg](cooleylogo2a.jpg)

Karen E. Deschaine

+1 858 550 6088

kdeschaine@cooley.com

February 28, 2023

Castle Biosciences, Inc.

505 S. Friendswood Drive, Suite 401

Friendswood, Texas 77546

Ladies and Gentlemen:

You have requested our opinion, as counsel to Castle Biosciences, Inc., a Delaware corporation (the "***Company***"), with respect to certain matters in connection with the filing by the Company of a Registration Statement on Form S-8 (the "***Registration Statement***") with the Securities and Exchange Commission covering the offering of an aggregate of up to 1,593,220 shares of the Company's Common Stock, $0.001 par value per share (the "***Shares***"), including (i) 1,327,684 shares issuable pursuant to the Company's 2019 Equity Incentive Plan (the "***Incentive Plan***") and (ii) 265,536 shares issuable pursuant to the Company's 2019 Employee Stock Purchase Plan (together with the Incentive Plan, the "***Plans***").

In connection with this opinion, we have examined and relied upon the Registration Statement and related prospectuses, the Plans, the Company's Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws, each as currently in effect, and originals or copies certified to our satisfaction of such records, documents, certificates, memoranda and other instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below. We have assumed the genuineness and authenticity of all documents submitted to us as originals, the conformity to originals of all documents submitted to us as copies thereof, the accuracy, completeness and authenticity of certificates of public officials; and the due authorization, execution and delivery, by all persons other than by the Company, of all documents where due authorization, execution and delivery are a prerequisite to the effectiveness thereof. As to certain factual matters, we have relied upon a certificate of an officer of the Company and have not sought independently to verify such matters.

Our opinion is expressed only with respect to the General Corporation Law of the State of Delaware. We express no opinion to the extent that any other laws are applicable to the subject matter hereof and express no opinion and provide no assurance as to compliance with any federal or state securities law, rule or regulation.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when sold and issued in accordance with the Plans, the Registration Statement and related prospectuses, will be validly issued, fully paid and nonassessable (except as to Shares issued pursuant to certain deferred payment arrangements under the Incentive Plan, which will be fully paid and nonassessable when such deferred payments are made in full).

Cooley LLP 10265 Science Center Drive, San Diego, CA 92121

t: (858) 550-6000 f: (858) 550-6420 cooley.com

------

![cooleylogo2a.jpg](cooleylogo2a.jpg)

February 28, 2023

Page Two

We consent to the filing of this opinion as an exhibit to the Registration Statement.

Sincerely,

Cooley LLP

By: <u>/s/ Karen E. Deschaine</u>&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Karen E. Deschaine

Cooley LLP 10265 Science Center Drive, San Diego, CA 92121

t: (858) 550-6000 f: (858) 550-6420 cooley.com

## Exhibit 23.1

**Exhibit 23.1**

**Consent of Independent Registered Public Accounting Firm**

We consent to the use of our report dated February 28, 2023, with respect to the consolidated financial statements of Castle Biosciences, Inc., and the effectiveness of internal control over financial reporting, incorporated herein by reference.

/s/ KPMG LLP

San Diego, California

February 28, 2023

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