# EDGAR Filing Document

**Accession Number:** 0001447362
**File Stem:** 0001628280-26-001909
**Filing Date:** 2026-1
**Character Count:** 19457
**Document Hash:** 0819f2cd2fe6844d8d1b87e128191eaf
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001628280-26-001909.hdr.sgml**: 20260113

**ACCESSION NUMBER**: 0001628280-26-001909

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 22

**CONFORMED PERIOD OF REPORT**: 20260111

**ITEM INFORMATION**: Results of Operations and Financial Condition

**ITEM INFORMATION**: Regulation FD Disclosure

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20260113

**DATE AS OF CHANGE**: 20260113

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** CASTLE BIOSCIENCES INC
- **CENTRAL INDEX KEY:** 0001447362
- **STANDARD INDUSTRIAL CLASSIFICATION:** SERVICES-MEDICAL LABORATORIES [8071]
- **ORGANIZATION NAME:** 08 Industrial Applications and Services
- **EIN:** 770701774
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-38984
- **FILM NUMBER:** 26528689

**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

?xml version='1.0' encoding='ASCII'? cstl-20260111

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**Washington, D.C. 20549**

**FORM 8-K**

**CURRENT REPORT**

**Pursuant to Section 13 or 15(d)**

**of the Securities Exchange Act of 1934**

**Date of Report (Date of earliest event reported): January 11, 2026**

**Castle Biosciences, Inc.**

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

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| | | |
|:---|:---|:---|
| **Delaware** | **001-38984** | **77-0701774** |
| **(state or other jurisdiction<br>of incorporation)** | **(Commission<br>File Number)** | **(I.R.S. Employer<br>Identification No.)** |

---

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| | |
|:---|:---|
| **505 S. Friendswood Drive, Suite 401**<br>**Friendswood, Texas** | **77546** |
| **(Address of principal executive offices)** | **(Zip Code)** |

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**Registrant's telephone number, including area code: (866) 788-9007**

**(Former name or former address, if changed since last report.)**

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐&nbsp;&nbsp;&nbsp;&nbsp;Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐&nbsp;&nbsp;&nbsp;&nbsp;Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐&nbsp;&nbsp;&nbsp;&nbsp;Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐&nbsp;&nbsp;&nbsp;&nbsp;Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

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| | | |
|:---|:---|:---|
| **Title of each class** | **Trading Symbol(s)** | **Name of each exchange on which registered** |
| **Common Stock, $0.001 par value per share** | **CSTL** | **The Nasdaq Global Market** |

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Indicate by check mark whether the registrant is an emerging growth company as defined in as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b–2 of the Securities Exchange Act of 1934 (§ 240.12b–2 of this chapter).

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 13(a) of the Exchange Act. ☐

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**Item 2.02&nbsp;&nbsp;&nbsp;&nbsp;Results of Operations and Financial Condition.**

On January 11, 2026, Castle Biosciences, Inc. (the "Company") issued a press release announcing certain preliminary performance results for the fourth quarter of 2025 and for the year ended December 31, 2025. A copy of the press release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

The information contained or incorporated in this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or otherwise subject to the liabilities of that section, nor shall it be deemed to be incorporated by reference into any filing under the Exchange Act or the Securities Act of 1933, as amended (the "Securities Act"), except as expressly set forth by specific reference in such filing to this Current Report on Form 8-K.

**Item 7.01&nbsp;&nbsp;&nbsp;&nbsp;Regulation FD Disclosure.**

On January 11, 2026, the Company made available the slide presentation attached hereto as Exhibit 99.2. Information from this slide presentation may also be used by the management of the Company in future meetings regarding the Company.

The information contained or incorporated in this Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.2, shall not be deemed "filed" for purposes of Section 18 of the Exchange Act or otherwise subject to the liabilities of that section, nor shall it be deemed to be incorporated by reference into any filing under the Exchange Act or the Securities Act except as expressly set forth by specific reference in such filing to this Current Report on Form 8-K.

**Item 9.01&nbsp;&nbsp;&nbsp;&nbsp;Financial Statements and Exhibits.**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) Exhibits.

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| | |
|:---|:---|
| **Exhibit**<br>**Number** |<br>**Description** |
| 99.1 | <u>[Press release issued January](cstlprelimresultsq42025.htm)[1](cstlprelimresultsq42025.htm)[1](cstlprelimresultsq42025.htm)[, 202](cstlprelimresultsq42025.htm)[6](cstlprelimresultsq42025.htm)[.](cstlprelimresultsq42025.htm)</u> |
| 99.2 | <u>[Slide presentation.](exhibit992cstlq42025prel.htm)</u> |
| 104 | Inline XBRL for the cover page of this Current Report on Form 8-K. |

---

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| |
|:---|
| **SIGNATURES** |
| Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has caused this report to be signed on its behalf by the undersigned hereunto duly authorized. |

---

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| | | |
|:---|:---|:---|
| | **CASTLE BIOSCIENCES, INC.** | **CASTLE BIOSCIENCES, INC.** |
| | By: | /s/ Frank Stokes |
| | | Frank Stokes |
| | | Chief Financial Officer |
| Date: January 11, 2026 |  |  |

---

## Exhibit 99.1

**Exhibit 99.1**

![image_0.jpg](image_0.jpg)

**<u>Castle Biosciences Announces Preliminary Unaudited Fourth Quarter and Full–Year 2025 Results</u>**

*2025* total revenue expected to exceed $340 million, above the previously guided range of $327-335 million

*2025* total test reports for our core revenue drivers (DecisionDx®-Melanoma, TissueCypher®) increased 37% over 2024

*Year-end 2025* cash, cash equivalents and marketable investment securities expected to be approximately *$300 million*

**FRIENDSWOOD, Texas – Jan. 11, 2026 –** Castle Biosciences, Inc. (Nasdaq: CSTL), a company improving health through innovative tests that guide patient care, today announced certain unaudited preliminary performance results for the fourth quarter and year ended Dec. 31, *2025*.

"We are extremely pleased with our excellent fourth quarter and full year preliminary results, which reflect both the strength of our innovative test portfolio and the dedication of the entire Castle team," said Derek Maetzold, president and chief executive officer of Castle Biosciences. "We exited 2025 exhibiting strong execution and leadership across our dermatologic and gastrointestinal franchises and a strong balance sheet, positioning us well, we believe, to capitalize on our growth opportunities in 2026 and beyond. This includes the November 2025, limited access launch of AdvanceAD-Tx™, our new test designed to help guide systemic treatment decisions for patients with moderate-to-severe atopic dermatitis, which materially expands our total addressable market."

**Preliminary, Unaudited Fourth Quarter Ended Dec. 31, 2025, Highlights**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Core revenue drivers:

• Fourth quarter 2025 total test reports for our core revenue drivers (DecisionDx-Melanoma, TissueCypher) increased 42% over the fourth quarter of 2024.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;◦ DecisionDx-Melanoma test reports delivered in the quarter were 10,022, compared to 8,672 in the fourth quarter of 2024.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;◦ TissueCypher Barrett's Esophagus test reports delivered in the quarter were 11,803, compared to 6,672 in the fourth quarter of 2024.

Additional tests:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;◦ AdvanceAD-Tx was launched on a limited access basis in November 2025. Of the approximately 150 clinician offices that were granted access, more than 50% ordered AdvanceAD-Tx during the first five weeks of clinical availability.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;◦ DecisionDx<sup>®</sup>-SCC test reports delivered in the quarter were 3,971, compared to 4,299 in the fourth quarter of 2024. Affecting fourth quarter test report volume was the change in Medicare coverage effective April 24, 2025, and re-focus of our commercial efforts.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;◦ MyPath<sup>®</sup> Melanoma test reports delivered in the quarter were 1,045, compared to 879 in the fourth quarter of 2024.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;◦ DecisionDx®-UM test reports delivered in the quarter were 395, compared to 424 in the fourth quarter of 2024.

**Preliminary, Unaudited Year Ended Dec. 31, 2025, Highlights**

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• 2025 total revenue expected to exceed $340 million, above the previously guided range of $327-335 million.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Core revenue drivers:

• 2025 total test reports for our core revenue drivers (DecisionDx-Melanoma, TissueCypher) increased 37% over 2024:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;◦ DecisionDx-Melanoma test reports delivered in 2025 were 39,083, compared to 36,008 in 2024.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;◦ TissueCypher Barrett's Esophagus test reports delivered in 2025 were 39,014, compared to 20,956 in 2024.

Additional tests:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;◦ DecisionDx-SCC test reports delivered in 2025 were 17,294, compared to 16,348 in 2024. Affecting twelve-month test report volume was the change in Medicare coverage effective April 24, 2025, and re-focus of our commercial efforts.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;◦ MyPath Melanoma test reports delivered in 2025 were 4,288, compared to 3,909 in 2024.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;◦ DecisionDx-UM test reports delivered in 2025 were 1,769, compared to 1,699 in 2024.

Discontinued tests:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;◦ IDgenetix test reports delivered in 2025 were 3,605, compared to 17,151 in 2024. The Company discontinued its IDgenetix test offering effective May 2025.

**Cash, Cash Equivalents and Marketable Investment Securities**

Year-end 2025 cash and cash equivalents are expected to be approximately $116 million. Additionally, the Company estimates that it held approximately $184 million in marketable investment securities as of year-end 2025.

**About Castle Biosciences**

Castle Biosciences (Nasdaq: CSTL) is a leading diagnostics company improving health through innovative tests that guide patient care. With a primary focus in dermatologic and gastroenterological disease, we develop personalized, clinically actionable solutions that help improve disease management and patient outcomes.

We put people first—empowering patients and clinicians and informing care decisions through rigorous science and advanced molecular tests that support more confident treatment planning. To learn more, visit <u>www.CastleBiosciences.com</u> and connect with us on <u>LinkedIn</u>, <u>Facebook</u>, <u>X</u> and <u>Instagram</u>.

DecisionDx-Melanoma, DecisionDx-CM*Seq*, i31-SLNB, i31-ROR, DecisionDx-SCC, MyPath Melanoma, AdvanceAD-Tx, TissueCypher, DecisionDx-UM, DecisionDx-PRAME and DecisionDx-UM*Seq* are trademarks of Castle Biosciences, Inc.

**Preliminary Results**

*Castle Biosciences has not completed the preparation of its financial statements for the fourth quarter or year ended Dec. 31, 2025. The preliminary, unaudited information presented in this press release for the quarter and year ended Dec. 31, 2025 is based on management's initial review of the information presented and its current expectations and is subject to adjustment as a result of, among other things, the completion of the Company's end-of-period reporting processes and related activities, including the audit by the Company's independent registered public accounting firm of the Company's financial statements. As such, any financial information contained in this press release may differ materially from the information reflected in the Company's financial statements as of and for the year ended Dec. 31, 2025. Additional information and disclosures would be required for a more complete understanding of the Company's financial position and results of operations as of and for the quarter and year ended Dec. 31, 2025. Accordingly, undue reliance should not be placed on this preliminary information.*

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**Forward-Looking Statements** 

**Investor Relations Contact:** 

Camilla Zuckero

czuckero@castlebiosciences.com

281-906-3868

**Media Contact:** 

Allison Marshall

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amarshall@castlebiosciences.com

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## Exhibit 99.2

![](exhibit992cstlq42025prel001.jpg)©2026 Castle Biosciences 1 Empowering people, informing care decisions Preliminary Unaudited Fourth Quarter and Year-End Results 2025 January 2026

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![](exhibit992cstlq42025prel002.jpg)

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![](exhibit992cstlq42025prel003.jpg)©2026 Castle Biosciences 3 Registered Trademarks DecisionDx-Melanoma, DecisionDx-CMSeq, i31-SLNB, i31-ROR, DecisionDx-SCC, MyPath Melanoma, AdvanceAD-Tx, TissueCypher, DecisionDx-UM, DecisionDx-PRAME and DecisionDx-UMSeq are trademarks of Castle Biosciences, Inc. Preliminary Results Castle Biosciences has not completed the preparation of its financial statements for the fourth quarter or year ended December 31, 2025. The preliminary, unaudited information presented herein for the quarter and year ended December 31, 2025 is based on management's initial review of the information presented and its current expectations and is subject to adjustment as a result of, among other things, the completion of the Company's end-of-period reporting processes and related activities, including the audit by the Company's independent registered public accounting firm of the Company's financial statements. As such, any financial information contained in this presentation may differ materially from the information reflected in the Company's financial statements as of and for the year ended December 31, 2025. Additional information and disclosures would be required for a more complete understanding of the Company's financial position and results of operations as of and for the quarter and year ended December 31, 2025. Accordingly, undue reliance should not be placed on this preliminary information.

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![](exhibit992cstlq42025prel004.jpg)©2026 Castle Biosciences 4 Clinical portfolio and pipeline tests Franchise Test Indication/Utility ~U.S. TAM1/Use Population Discovery Development Commercial Dermatology Cutaneous melanoma/ risk of sentinel lymph node positivity, recurrence & metastasis ~$540M/ 130k patients w/ invasive CM Cutaneous squamous cell carcinoma/ risk of metastasis & local recurrence; likelihood of benefit from ART ~$820M/ 200k patients with high-risk SCC Ambiguous melanocytic lesions/ malignant potential ~$600M/ 300k patients w/ ambiguous lesions Atopic dermatitis/ therapy guidance ~$33B/ 13.2 million patients ages 12+ in U.S. one- year prevalence SciBase collaboration pipeline test Atopic dermatitis/ prediction of flares Gastroenterology Barrett's esophagus/ risk of progression to high-grade dysplasia or esophageal adenocarcinoma ~$1B Pipeline test (non-endoscopic collection device) GI disease/ diagnostic test Ophthalmology Uveal melanoma/ risk of metastasis ~$10M 1U.S. TAM= Total addressable market based on estimated patient population assuming average reimbursement rate among all payors.

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![](exhibit992cstlq42025prel005.jpg)©2026 Castle Biosciences 5 Preliminary Fourth Quarter and Year-end 2025 Performance Results1 (unaudited) 4Q25 4Q24 2025 2024 Revenue To be announced $86.3 million Expected to exceed $340 million, above the previously guided range of $327-335 million2 $332.1 million Cash, cash equivalents & marketable investment securities As of 12/31/25 ~$300 million (expected) Total Test Reports 27,236 24,071 105,053 96,071 • DecisionDx- Melanoma 10,022 8,672 39,083 36,008 • TissueCypher 11,803 6,672 39,014 20,956 • DecisionDx-SCC3 3,971 4,299 17,294 16,348 • MyPath Melanoma 1,045 879 4,288 3,909 • DecisionDx-UM 395 424 1,769 1,699 • IDgenetix4 0 3,125 3,605 17,151 1. Castle expects to report its audited consolidated financial statements and complete financial and operational results for its fiscal year ended December 31, 2025, in February 2026. 2. Castle previously provided guidance for full-year 2025 total revenue of between $327-335 million on November 3, 2025. 3. Affecting fourth quarter and twelve months ended December 31, 2025 revenue and test report volume was the change in Medicare coverage effective April 24, 2025, and re-focus of our commercial efforts. 4. The Company discontinued its IDgenetix test offering effective May 2025.

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![](exhibit992cstlq42025prel006.jpg)©2026 Castle Biosciences 6 Preliminary Unaudited Fourth Quarter and Full–Year 2025 Results Highlights1 1 Announced launch of AdvanceAD-Tx, the Company's test designed to guide systemic therapy decision making in patients ages 12 and older with moderate-to-severe atopic dermatitis 5 2025 year-end cash, cash equivalents & marketable investment securities expected to be approximately $300 million Achieved provided guidance of high single-digit percentage volume growth at 9% for DecisionDx-Melanoma for full year 2025 over 2024 6 Recognized by the Houston Chronicle as a Houston Top Workplace, which celebrates people-focused, standout workplace cultures 2 3 1. Castle expects to report its audited consolidated financial statements and complete financial and operational results for its fiscal year ended December 31, 2025, in February 2026. 4 1 Total test reports for our core revenue drivers (DecisionDx-Melanoma, TissueCypher) increased 42% in Q4 2025 year over year, driving 37% growth for full year 2025 Delivered 86% volume growth for TissueCypher for the full year 2025 compared to the full year 2024

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![](exhibit992cstlq42025prel007.jpg)©2026 Castle Biosciences 7 Thank You

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