July 25, 2019

Rajiv Shukla
Chief Executive Officer
Constellation Alpha Capital Corp.
Emerald View, Suite 400
2054 Vista Parkway
West Palm Beach, FL 33411

       Re: Constellation Alpha Capital Corp.
           Amendment No. 1 to Registration Statement on Form S-4
           Filed July 18, 2019
           File No. 333-232181

Dear Mr. Shukla:

      We have reviewed your amended registration statement and have the
following
comments. In some of our comments, we may ask you to provide us with
information so we
may better understand your disclosure.

       Please respond to this letter by amending your registration statement
and providing the
requested information. If you do not believe our comments apply to your facts
and
circumstances or do not believe an amendment is appropriate, please tell us why
in your
response.

       After reviewing any amendment to your registration statement and the
information you
provide in response to these comments, we may have additional comments. Unless
we note
otherwise, our references to prior comments are to comments in our July 12,
2019 letter.

Amendment No. 1 to Form S-4 filed July 18, 2019

The Business Combination
Background of the Business Combination, page 95

1.     We note your revised disclosure regarding Cowen and Company acting as
the underwriter
       in your initial public offering and facilitating the PIPE financing. It
appears Cowen also
       participated in the negotiations with DermTech as indicated by the
February 13, 2019 and
       March 21, 2019 meetings. Please discuss in greater detail the role Cowen
played during
       the negotiations as previously requested in comment 7.
2.     We note your response to comment 5. Please disclose the reason(s)
conditions precedent
       were not fulfilled and resulted in the termination of the merger.
 Rajiv Shukla
FirstName LastNameRajiv Shukla
Constellation Alpha Capital Corp.
Comapany NameConstellation Alpha Capital Corp.
July 25, 2019
July 25, 2019 Page 2
Page 2
FirstName LastName
Material U.S. Federal Income Tax Consequences of the Business Combination, page
106

3.       We reissue comment 8. We note the revised statement that in the
opinion of counsel, the
         following is a description of the material federal income tax
consequences of the business
         combination. Please revise the disclosure to clearly state the opinion
of counsel. A
         description of the law is not sufficient. For guidance, see Section
III.C.2 of Staff Legal
         Bulletin No. 19.
Material U.S. Federal Income Tax Consequences of the Domestication, page 135

4.       We note your response to comment 10. We note the revised statement
that in the opinion
         of counsel, the following is a description of the material federal
income tax consequences
         of the business combination. Please revise the disclosure to clearly
state the opinion of
         counsel. A description of the law is not sufficient. For guidance, see
Section III.C.2 of
         Staff Legal Bulletin No. 19. In addition, we note the statement that
US shareholders
         "should not" recognize taxable gain or loss as a result of the
domestication. Please
         explain why you cannot give a "will" opinion and describe the degree
of uncertainty. For
         guidance, see Section III.C.4 of Staff Legal Bulletin No. 19.
DermTech Management's Discussion and Analysis of Financial Condition and
Results of
Operations, page 196

5.       We reissue comment 13. The Management's Discussion and Analysis
section is one of
         the most critical aspects of your disclosure. As such, we request that
you revise this
         section to provide a more detailed executive overview to discuss the
events, trends, and
         uncertainties that management views as most critical to your future
revenues, financial
         position, liquidity, plan of operations, and results of operations, to
the extent known and
         foreseeable. To assist you in this regard, please refer to the
Commission Guidance
         Regarding Management's Discussion and Analysis of Financial Condition
and Results of
         Operations, Release Nos. 33-8350 (December 19, 2003) at
         http://www.sec.gov/rules/interp/33-8350.htm.
6.       Please revise the disclosure of convertible bridge notes on page 197
to discuss the
         conversion feature. Also, disclose whether the PIPE transaction will
be a qualified
         financing that will result in automatic conversion of the notes.
Potential Payments and Other Benefits Awardable in Connection with the Business
Combination, page 222

7.       We note your response to comment 15. Please disclose the information
provided in your
         response regarding the quantification of the immediate vesting of the
securities, including
         the expectation that the trading value of shares will be substantially
lower due to the
         difference between the Nasdaq Capital Market price per share and the
PIPE financing
         price per share. In addition, consider adding risk factor disclosure.
 Rajiv Shukla
Constellation Alpha Capital Corp.
July 25, 2019
Page 3
DermTech Director Compensation, page 223

8.       We note your response to comment 16. Please revise to include the
consulting services
         fee in the "All Other Compensation" column and include a footnote
identifying and
         quantifying the amount. See Item 402(r)(2)(vii)(F) of Regulation S-K.
Unaudited Pro Forma Condensed Consolidated Balance Sheet, page 228

9.       Please explain in further detail why deferred underwriting fees are
being reduced by
         $2,843,750 in adjustment 6 to the pro forma balance sheet. Also, as
Note 6 to
         Constellation's audited financial statements on page F-61 indicates
that the
         deferred underwriting fees will be paid upon the closing of a business
combination from
         amounts held in the trust account, please explain why an adjustment to
cash reflecting
         payment of these deferred underwriting fees has not been made to the
pro forma balance
         sheet.
       You may contact Linda Cvrkel at 202-551-3813 or Craig Arakawa at
202-551-3650 if
you have questions regarding comments on the financial statements and related
matters. Please
contact Michael Killoy at 202-551-7576 or Pam Howell at 202-551-3357 with any
other
questions.



                                                             Sincerely,
FirstName LastNameRajiv Shukla
                                                             Division of
Corporation Finance
Comapany NameConstellation Alpha Capital Corp.
                                                             Office of
Beverages, Apparel and
July 25, 2019 Page 3                                         Mining
FirstName LastName