Castle Biosciences, Inc. Common Stock CG 46th Annual Growth Conference

Yeah, sure. So two key drivers in the business are our DecisionDx-Melanoma and TissueCypher. We saw good performance in both. Modest, I would say, incremental ASP progress across both through the first half of the year. So I think the drivers there are continued penetration, continued physician conversion, and in both tests, really expanding the pool of a physician's patients that they want to test with those two tests. We raised our guidance a little bit more than the beat, so I think we see that signals some optimism in where things go in the second half and continued good performance on the whole franchise.

We still see it as this year a mid to high single-digit volume growth test. We're at a bit of a more mature penetration point there. We use about 130,000 melanomas a year, invasive melanomas. SEER data's about 100, but there are some really good publications, there are four actually, that suggest melanoma's under-reported by between 30% and 70%. The dynamic there is melanomas are usually reported in a community or diagnosed in a community derm office, and those offices sometimes don't have experience or awareness of SEER reporting, and so a lot of those cases don't get reported. The publications show 30% to 70%. We use 30% to be conservative, so that gets you 130,000, if that's the right number. If that's the number, we're testing about a third of the patients at this point.

We probably have two thirds to maybe a little more of the physicians have used our test or the healthcare practitioners, providers, have used our test in the last year. We're at a little bit chunkier point in the penetration curve. I think we continue to convert physicians, but good, solid performance there, and I think that's going to continue to be an important revenue driver for us.

The compensation structure still skews almost totally toward melanoma.

Okay. We are building a longer-term value franchise in our derm business.

We also have our SCC test, which is currently poorly reimbursed and not covered by Medicare, and we have our MyPath Melanoma test as well. We have a fairly robust derm portfolio there, and we have to sort of balance Q2. What are we doing for Q2 versus what we are doing for 2027, 2028? We have some attention on some other testing that the sales force has directed, but by and large, most of what they are doing is focused on melanoma.

I think we still have plenty of runway in melanoma. Other modalities, the percentage of testing is higher than in melanoma. You have thyroid at 60%-ish, 65%-ish. I think prostate is in the 50% maybe. One of the differences we have is in melanoma, we have one primary test, and really one test with quality data. So the overall testing penetration is a little bit more subdued, but I think we can continue to grow that. How long does it take to get to those points, I think, is the question. But every physician meeting, every day, we have a physician that somehow, despite 12, 14 years of selling this test, we still have some physicians who still are not aware of it, have not heard of it, have not been educated on the benefits of it. So we continue to find new physicians to convert.

Within those physicians, we do a ton of R&D and study work to demonstrate the benefit of testing all their patients. So you have a new store and a same store opportunity there, if you think about it that way from the physician perspective. Physicians will frequently do their own risk stratification. Maybe they are comfortable at a millimeter and below is a low-risk melanoma, so I do not need a test. Millimeter and above is high risk. In the first place, we have data that shows that we are clinically actionable all the way down to three-tenths of a millimeter. Below that, there is no actionability, no benefit to testing. But anything above three-tenths, there is benefit. On top of that, you have the opportunity to just break it down for a physician, just from a practical perspective.