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Expression Pathology Hopes to Transform Archived Tissues into Gold Mines of Samples


It may not be the sexiest problem in proteomics, but the issue of how to gather enough tissue samples for array or mass spec-based experiments is one many researchers struggle with. Gaithersburg, Md.-based start-up Expression Pathology, founded two years ago by a group of former pathology and tissue analysis scientists from the NCI and Life Technologies, hopes to begin offering services this year that would solve that problem.

“A lot of people talk about fresh frozen tissue, [but] it’s hard to procure, it’s hard to handle, it’s expensive,” Peter Tunon, vice president, business development for EPI, told ProteoMonitor. “If you use archival tissue — formalin-fixed paraffin embedded tissue — you can go back and look at samples from decades ago and you have extensive collections you can mine.”

In the next few months, EPI plans to begin offering to pharma front-end sample preparation and custom protein array services that would employ the technology it says it has developed to use this untapped resource of fixed tissue. The company hopes to put a variety of array and mass spec-based products on the market beginning in 2005. In the meantime, it is working hard at winning over investors in a private placement, and at least some are taking the bait: This week, EPI announced that it has received $300,000 in angel investment and Maryland technology funds. The company will follow the private placement with a Series A funding round, Tunon said.

EPI’s flagship technology, for which a patent is currently pending, is a process called Liquid Tissue, which makes it possible to liquefy the proteins in a fixed tissue sample and prepare the proteins for spotting on a chip or for analysis by mass spec, according to Tunon. The company has also developed ExCellerator, an alternative to laser capture microdissection that Tunon claims is more easily scaleable to high-throughput workflows, although he says that EPI has not yet tried any such scaling up. “We’re currently at a very early prototype stage,” he said. The microdissection technology — based on a technology called laser-induced forward transfer — differs from LCM in that it is a non-contact method. Tunon said it could be adapted not only for the dissection process, but for protein arraying as well. “Using our laser technology, we can print with great reproducibility very dense arrays: We believe we can make arrays with thousands of spots on a [slide-sized] array,” he said. Thus far EPI has only made a few of these very dense arrays, but Tunon believes the process can eventually be scaled up.

The company has garnered some early interest, particularly from big pharma, that it hopes to turn into early customers. Tunon said that EPI is currently in discussions with “several large pharmas which are curious about getting early access,” and that the company has already “signed a couple of agreements to do joint research with a couple of different companies, including one very large biopharma and several small biotechs, [and one large institution], and we’re currently discussing with a few others.” He said that the early collaborations would be important “to show how well it works, to get a couple of good applications out there, so we can go out and start to commercialize this on an early access basis in the next three to six months,” as well as to attract further investment.

The potential applications of EPI’s arrays, according to Tunon, include anything for which one would want to screen antibodies in a high-throughput fashion — in particular, drug target validation and predictive toxicology. For the mass spec sample prep service, differential expression analyses would be the main application. Although the mass spec prep service has garnered a lot of enthusiasm, it is a newer iteration, and so “we haven’t had time to start capitalizing on it yet,” Tunon said. Tunon had much more specific examples on hand for applying the arrays. “We were talking to someone just now with 100 different targets,” he said. “If you screen 100 different targets against a whole bunch of different normal tissues from various parts of the body, and you’re going to do this multiple times, we would be providing a very quick and easy tool to stain, read, and quantitate with our liquid tissue arrays.”

EPI has not yet decided exactly what products it wants to release on the market, but one that it will not release is the Liquid Tissue technology itself. “We keep the Liquid Tissue process in-house — that’s our big IP,” Tunon said. The ExCellerator technology will remain in-house initially as well, although EPI “may, if we find a suitable partner, commercialize that as an instrument platform,” Tunon said. ExCellerator might also eventually be released as a protein arrayer platform. Potential products that have generated particular interest include a custom brain tissue chip, and a variety of cancer screening chips. “We have so many possibilities — we just have to figure out what people would buy,” Tunon said.


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