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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
(Amendment No.1)
CYTYC Corporation
(Name of Issuer)
Common Stock
(Title of Class of Securities)
232946103
(CUSIP Number)
February 29, 2000
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:
/_X_/ Rule 13d-2(d)
The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject
class of securities, and for any subsequent amendment containing
information which would alter disclosures provided in a prior
cover page.
The information required on the remainder of this cover page shall not be
deemed to be "filed" for the purpose of Section 18 of the Securities
Exchange Act of 1934 ("Act") or otherwise subject to the liabilities
of that section of the Act but shall be subject to all other provisions
of the Act (however, see the Notes).
Potential persons who are to respond to the collection of information
contained in this form are not required to respond unless the form
displays a currently valid OMB control number.
SEC 1745 (3-98) Page 1 of 10
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CUSIP No. 232946103 13G Page 2 of 10
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1 NAME OF REPORTING PERSONS
IRS IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
RS Investment Management Co. LLC
- ----------------------------------------------------------------
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
(a)/ X /
(b)/ /
- ----------------------------------------------------------------
3 SEC USE ONLY
- ----------------------------------------------------------------
4 CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware
- ----------------------------------------------------------------
NUMBER OF 5 SOLE VOTING POWER
SHARES -0-
BENEFICIALLY ---------------------------------------
OWNED BY 6 SHARED VOTING POWER
EACH -2,214,500-
REPORTING ---------------------------------------
PERSON 7 SOLE DISPOSITIVE POWER
WITH -0-
---------------------------------------
8 SHARED DISPOSITIVE POWER
-2,214,500-
- ----------------------------------------------------------------
9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
-2,214,500-
- ----------------------------------------------------------------
10 CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (See
Instructions)
- ----------------------------------------------------------------
11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
11.8%
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12 TYPE OF REPORTING PERSON (See Instructions)
OO, HC
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CUSIP No. 232946103 13G Page 3 of 10
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1 NAME OF REPORTING PERSONS
IRS IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
RS Investment Management, L.P.
- ----------------------------------------------------------------
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
(a)/ X /
(b)/ /
- ----------------------------------------------------------------
3 SEC USE ONLY
- ----------------------------------------------------------------
4 CITIZENSHIP OR PLACE OF ORGANIZATION
California
- ----------------------------------------------------------------
NUMBER OF 5 SOLE VOTING POWER
SHARES -0-
BENEFICIALLY ---------------------------------------
OWNED BY 6 SHARED VOTING POWER
EACH -1,267,300-
REPORTING ---------------------------------------
PERSON 7 SOLE DISPOSITIVE POWER
WITH -0-
---------------------------------------
8 SHARED DISPOSITIVE POWER
-1,267,300-
- ----------------------------------------------------------------
9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
-1,267,300-
- ----------------------------------------------------------------
10 CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (See
Instructions)
- ----------------------------------------------------------------
11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
6.7%
- ----------------------------------------------------------------
12 TYPE OF REPORTING PERSON (See Instructions)
IA, PN
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CUSIP No. 232946103 13G Page 4 of 10
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1 NAME OF REPORTING PERSONS
IRS IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
RS Investment Management, Inc.
- ----------------------------------------------------------------
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
(a)/ X /
(b)/ /
- ----------------------------------------------------------------
3 SEC USE ONLY
- ----------------------------------------------------------------
4 CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware
- ----------------------------------------------------------------
NUMBER OF 5 SOLE VOTING POWER
SHARES -0-
BENEFICIALLY ---------------------------------------
OWNED BY 6 SHARED VOTING POWER
EACH -947,200-
REPORTING ---------------------------------------
PERSON 7 SOLE DISPOSITIVE POWER
WITH -0-
---------------------------------------
8 SHARED DISPOSITIVE POWER
-947,200-
- ----------------------------------------------------------------
9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
-947,200-
- ----------------------------------------------------------------
10 CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (See
Instructions)
- ----------------------------------------------------------------
11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
5.0%
- ----------------------------------------------------------------
12 TYPE OF REPORTING PERSON (See Instructions)
IA, CO
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CUSIP No. 232946103 13G Page 5 of 10
- ----------------------------------------------------------------
1 NAME OF REPORTING PERSONS
IRS IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
RS Emerging Growth Fund
- ----------------------------------------------------------------
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
(a)/ X /
(b)/ /
- ----------------------------------------------------------------
3 SEC USE ONLY
- ----------------------------------------------------------------
4 CITIZENSHIP OR PLACE OF ORGANIZATION
Massachusetts
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NUMBER OF 5 SOLE VOTING POWER
SHARES -0-
BENEFICIALLY ---------------------------------------
OWNED BY 6 SHARED VOTING POWER
EACH -934,600-
REPORTING ---------------------------------------
PERSON 7 SOLE DISPOSITIVE POWER
WITH -0-
---------------------------------------
8 SHARED DISPOSITIVE POWER
-934,600-
- ----------------------------------------------------------------
9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
-934,600-
- ----------------------------------------------------------------
10 CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (See
Instructions)
- ----------------------------------------------------------------
11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
5.0%
- ----------------------------------------------------------------
12 TYPE OF REPORTING PERSON (See Instructions)
IV
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CUSIP No. 232946103 13G Page 6 of 10
ITEM 1.
(a) The name of the issuer is CYTYC Corporation (the
"Issuer").
(b) The principal executive office of the Issuer is located at
85 Swanson Road, Boxborough, MA 01719.
ITEM 2.
(a-c) See Annex I for information on the persons filing this
statement (collectively, the "Filers").
(d) This statement relates to shares of common stock of the Issuer
(the "Stock").
(e) The CUSIP number of the Stock is 232946103.
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CUSIP No. 232946103 13G Page 7 of 10
ITEM 3. If this statement is filed pursuant to rule 240.13d-1(b) or 240.13d-
2(b) or (c), check whether the person filing is a:
(a) ___ Broker or dealer registered under section 15 of the Act (15
U.S.C. 78o).
(b) ___ Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).
(c) ___ Insurance company as defined in section 3(a)(19) of the Act
(15 U.S.C. 78c).
(d) ___ Investment company registered under section 8 of the
Investment Company Act of 1940 (15 U.S.C. 80a-8).
(e) ___ An investment adviser in accordance with 240.13d-
1(b)(1)(ii)(E).
(f) ___ An employee benefit plan or endowment fund in accordance with
240.13d-1(b)(1)(ii)(F).
(g) ___ A parent holding company or control person in accordance with
240.13d-1(b)(1)(ii)(G)
(h) ___ A savings association as defined in section 3(b) of the
Federal Deposit Insurance Act (12 U.S.C. 1813).
(i) ___ A church plan that is excluded from the definition of an
investment company under section 3(c)(14) of the Investment Company Act of 1940
(15 U.S.C. 80a-3).
(j) _X_ Group, in accordance with section 240.13d-1(b)(1)(ii)(J)
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CUSIP No. 232946103 13G Page 8 of 10
ITEM 4. OWNERSHIP
See Items 5-9 and 11 on the cover page for each Filer.
ITEM 5. OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS
Not applicable.
ITEM 6. OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON
RS Investment Management, L.P. and RS Investment Management, Inc. are
registered investment advisers whose clients have the right to receive
or the power to direct the receipt of dividends from, or the proceeds
from the sale of, the Stock. No client other than RS Emerging Growth Fund
owns greater than 5% of the Stock.
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CUSIP No. 232946103 13G Page 9 of 10
ITEM 7. IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE
SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY
Not applicable.
ITEM 8. IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP
RS Investment Management, L.P. and RS Investment Management, Inc. are
registered investment advisers. RS Investment Management Co. LLC is the
General Partner of RS Investment Management, L.P. and the
controlling shareholder of RS Investment Management, Inc.
RS Emerging Growth Fund is an investment company. RS Investment
Management, Inc. is the investment adviser to
RS Emerging Growth Fund.
ITEM 9. NOTICE OF DISSOLUTION OF GROUP
Not applicable.
ITEM 10. CERTIFICATION
By signing below I certify that, to the best of my knowledge and belief,
the securities referred to above were acquired and are held in the
ordinary course of business and were not acquired and are not held
for the purpose of or with the effect of changing or influencing the
control of the issuer of the securities and were not acquired and are
not held in connection with or as a participant in any transaction
having that purpose or effect.
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief,
I certify that the information set forth in this statement is true,
complete and correct.
Dated: March 5, 2000
RS INVESTMENT MANAGEMENT CO. LLC
By: /s/ G. Randall Hecht
G. Randall Hecht
Chief Executive Officer
RS INVESTMENT MANAGEMENT, L.P.
By: RS Investment Management Co. LLC
By: /s/ G. Randall Hecht
G. Randall Hecht
Chief Executive Officer
RS INVESTMENT MANAGEMENT, INC.
By: RS Investment Management Co. LLC
By: /s/ G. Randall Hecht
G. Randall Hecht
Chief Executive Officer
RS EMERGING GROWTH FUND
By: RS Investment Trust
By: /s/ G. Randall Hecht
President
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CUSIP No. 232946103 13G Page 10 of 10
EXHIBIT A
JOINT FILING AGREEMENT
The undersigned hereby agree that they are filing this statement jointly
pursuant to Rule 13d-1(f)(1). Each of them is responsible for the timely
filing of the Schedule 13G and any amendments thereto, and for the
completeness and accuracy of the information concerning such person
contained therein; but none of them is responsible for the completeness
or accuracy of the information concerning the other persons making the
filing, unless such person knows or has reason to believe that such
information is accurate.
Dated: March 5, 2000
RS INVESTMENT MANAGEMENT CO. LLC
By: /s/ G. Randall Hecht
G. Randall Hecht
Chief Executive Officer
RS INVESTMENT MANAGEMENT, L.P.
By: RS Investment Management Co. LLC
By: /s/ G. Randall Hecht
G. Randall Hecht
Chief Executive Officer
RS INVESTMENT MANAGEMENT, INC.
By: RS Investment Management Co. LLC
By: /s/ G. Randall Hecht
G. Randall Hecht
Chief Executive Officer
RS EMERGING GROWTH FUND
By: RS Investment Trust
By: /s/ G. Randall Hecht
President
Annex I
This Annex identifies certain entities which may be filing parties
of the attached Schedule or which may be referred to in the filing.
The principal office and principal place of business of the following
entities is 388 Market Street, Suite 200, San Francisco, CA 94111:
I. (a) RS Investment Management Co. LLC is a Delaware Limited
Liability Company.
(b) holding company
II. (a) RS Investment Management, L.P. is a California Limited
Partnership.
(b) registered investment adviser
III. (a) RS Investment Management, Inc. is a Delaware corporation.
(b) registered investment adviser
IV. (a) RS Emerging Growth Fund is part of a Massachusetts business trust.
(b) investment company
RS Investment Management, L.P. and RS Investment Management, Inc. are
registered investment advisers. RS Investment Management Co. LLC is the
General Partner of RS Investment Management, L.P. and the
controlling shareholder of RS Investment Management, Inc.
RS Emerging Growth Fund is an investment company.
RS Investment Management, Inc. is the investment adviser to
RS Emerging Growth Fund.
