SC TO-T/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

________________

Amendment No. 10

to

SCHEDULE TO

(Rule 14d-100)

Tender Offer Statement under Section 14(d)(1) or 13(e)(1) of

the Securities Exchange Act of 1934

VENTANA MEDICAL SYSTEMS, INC.

(Name of Subject Company)

ROCKET ACQUISITION CORPORATION

ROCHE HOLDING LTD

(Names of Filing Persons — Offeror)

Common Stock, Par Value $0.001 Per Share

(including the associated preferred stock purchase rights)

(Title of Class of Securities)

________________

92276H106

(Cusip Number of Class of Securities)

Beat Kraehenmann

Roche Holding Ltd

Grenzacherstrasse 124

CH-4070 Basel

Switzerland

Telephone: +41-61-688-1111

(Name, Address and Telephone Number of Person Authorized to ReceiveNotices

and Communications on Behalf of Filing Persons)

Copies to:

Christopher Mayer

Davis Polk & Wardwell

450 Lexington Avenue

New York, New York 10017

Telephone: (212) 450-4000

CALCULATION OF FILING FEE

Transaction Valuation*	Amount of Filing Fee**
$2,978,902,500	$91,452.31

* Estimated for purposes of calculating the filing fee only. This amount assumes the purchase of all 33,668,000 shares of common stock of Ventana Medical Systems, Inc. outstanding as of March 31, 2007, all options outstanding as of March 31, 2007 with respect to 6,022,000 shares of common stock of Ventana, and all restricted stock and restricted stock units outstanding as of March 31, 2007 with respect to 28,700 shares of common stock of Ventana. The number of outstanding shares, options, and restricted stock and restricted stock units is contained in Ventana’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2007.

** The amount of the filing fee is calculated in accordance with Rule 0-11 of the Securities Exchange Act of 1934, as amended, by multiplying the transaction valuation by 0.0000307.

R Check box if any part of the fee is offset as provided by Rule 0-11(a)(2) and identify the filing with which the offsetting fee was previously paid. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

Amount Previously Paid:	$91,452.31	Filing Party:	Roche Holding Ltd
Form or Registration No.:	SC TO-T	Date Filed:	June 27, 2007

£ Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:

R third-party tender offer subject to Rule 14d-1.

£ issuer tender offer subject to Rule 13e-4.

£ going-private transaction subject to Rule 13e-3.

£ amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer.  £

Items 1 through 9.

This Amendment No. 10 to Tender Offer Statement on Schedule TO (the “Schedule TO”) amends and supplements the statement originally filed on June 27, 2007 by Roche Holding Ltd, a joint stock company organized under the laws of Switzerland (“Parent”), and Rocket Acquisition Corporation (the “Purchaser”), a Delaware corporation and an indirect wholly owned subsidiary of Parent. This Schedule TO relates to the offer by the Purchaser to purchase all outstanding shares of common stock, par value $0.001 per share (together with the associated preferred stock purchase rights, the “Shares”), of Ventana Medical Systems, Inc., a Delaware corporation (the “Company”), at $75.00 per Share, net to the seller in cash, without interest and less applicable withholding taxes, upon the terms and subject to the conditions set forth in the Offer to Purchase, dated June 27, 2007 (the “Offer to Purchase”), and in the related Letter of Transmittal (which, together with any amendments or supplements thereto, collectively constitute the “Offer”).

The information set forth in the Offer to Purchase, including all schedules thereto, and the related Letter of Transmittal is expressly incorporated herein by reference with respect to all of the items of this Schedule TO, except as otherwise set forth below.

All capitalized terms used in this Amendment No. 10 without definition have the meanings ascribed to them in the Schedule TO.

Item 10.  Financial Statements.

Not applicable.

Item 11. Additional Information.

On August 21, 2007, the United States District Court for the District of Arizona granted Roche's motion for a preliminary injunction enjoining Ventana from taking action to apply or enforce the Arizona Business Combination Act or the Arizona Control Share Act with respect to the Purchaser or the Offer.

Item 12.  Exhibits.

Item 12 is hereby amended and supplemented with the following information:

Exhibit (a)(5)(x) Press Release issued by Roche Holding Ltd, dated August 22, 2007.

SIGNATURES

After due inquiry and to the best knowledge and belief of the undersigned, each of the undersigned certify that the information set forth in this statement is true, complete and correct.

Date: August 22, 2007

ROCKET ACQUISITION CORPORATION
By:	/s/ Beat Kraehenmann
	Name:	Beat Kraehenmann
	Title:	Secretary
ROCHE HOLDING LTD
By:	/s/ Steve Krognes
	Name:	Steve Krognes
	Title:	Authorized Signatory
By:	/s/ Beat Kraehenmann
	Name:	Beat Kraehenmann
	Title:	Authorized Signatory

EXHIBIT INDEX

Exhibit No.	Description
(a)(1)(i)	Offer to Purchase dated June 27, 2007*
(a)(1)(ii)	Letter of Transmittal*
(a)(1)(iii)	Notice of Guaranteed Delivery*
(a)(1)(iv)	Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees*
(a)(1)(v)	Letter to Clients for use by Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees*
(a)(1)(vi)	Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9*
(a)(1)(vii)	Summary Advertisement dated June 27, 2007*
(a)(5)(i)	Press Release issued by Roche Holding Ltd, dated June 25, 2007*
(a)(5)(ii)	Complaint filed in the Court of Chancery of the State of Delaware in and for New Castle County on June 29, 2007*
(a)(5)(iii)	Complaint filed in the United States District Court for the District of Arizona on June 29, 2007*
(a)(5)(iv)	Press Release issued by Roche Holding Ltd, dated July 11, 2007*
(a)(5)(v)	Excerpt from an Investor Presentation by Roche Holding Ltd, dated July 19, 2007*
(a)(5)(vi)	Transcript of an Investor Presentation by Roche Holding Ltd, dated July 19, 2007*
(a)(5)(vii)	Press Release issued by Roche Holding Ltd, dated July 25, 2007*
(a)(5)(viii)	Press Release issued by Roche Holding Ltd, dated July 26, 2007*
(a)(5)(ix)	Press Release issued by Roche Holding Ltd, dated August 21, 2007*
(a)(5)(x)	Press Release issued by Roche Holding Ltd, dated August 22, 2007
(b)	Not applicable
(c)	Not applicable
(d)	Not applicable
(f)	Not applicable
(g)	Not applicable
(h)	Not applicable

________________

* Previously filed

EX-99.A.5.X

EXHIBIT (a)(5)(x)

Media Release

Basel, August 22, 2007

United States District Court for the District of Arizona Grants Roche's

Motion for Preliminary Injunction

Roche (SWX: ROG.VX; RO.S) announced that, on August 21, 2007, the United States District Court for the District of Arizona granted Roche's motion for a preliminary injunction enjoining Ventana Medical Systems Inc. (NASDAQ: VMSI) from taking action to apply or enforce certain antitakover provisions of the Arizona Revised Statutes (sections 10-2721 through 10-2727 and sections 10-2741 through 10-2743) with respect to Roche or Roche's tender offer to purchase all outstanding shares of common stock of Ventana.

On June 27, 2007, Roche commenced a tender offer to acquire all of the outstanding common shares of Ventana for $75.00 per share in cash.  This price represents a 44% premium to Ventana’s close of $51.95 on June 22, 2007 (the last trading day prior to the announcement of Roche’s offer) and a 55% premium to its three-month average as of the same date of $48.30.

Greenhill & Co. and Citi are acting as financial advisors to Roche and Davis Polk & Wardwell is acting as legal counsel.

About Roche

Headquartered in Basel, Switzerland, Roche is one of the world’s leading research-focused healthcare groups in the fields of pharmaceuticals and diagnostics. As the world’s biggest biotech company and an innovator of products and services for the early detection, prevention, diagnosis and treatment of diseases, the Group contributes on a broad range of fronts to improving people’s health and quality of life. Roche is the world leader in in-vitro diagnostics and drugs for cancer and transplantation, a market leader in virology and active in other major therapeutic areas such as autoimmune diseases, inflammation, metabolic disorders and diseases of the central nervous system. In 2006 sales by the Pharmaceuticals Division totaled 33.3 billion Swiss francs, and the Diagnostics Division posted sales

F. Hoffmann-La Roche Ltd. CH-4070 Basel Corporate ommunications Tel. +41 61 - 688 88 88 Fax +41 61 - 688 27 75 http://www.roche.com

of 8.7 billion Swiss francs. Roche has R&D agreements and strategic alliances with numerous partners, including majority ownership interests in Genentech and Chugai, and invests approximately 7 billion Swiss francs a year in R&D. Worldwide, the Group employs about 75,000 people.

Roche’s Diagnostics Division offers a uniquely broad product portfolio and supplies a wide array of innovative testing products and services to researchers, physicians, patients, hospitals and laboratories world-wide.

Roche commenced operations in the U.S. over 100 years ago and these operations include research and development centers that conduct leading-edge work in advancing disease detection and treatment. Our diagnostics and pharmaceuticals businesses in the U.S. employ more than 20,000 people and generate approximately $10 billion in sales (including Genentech), accounting for about 40% of the Roche Group's global annual revenues.

For further information, please visit www.roche.com.

All trademarks used or mentioned in this release are protected by law.

Further information

- All documents on the offer to Ventana’s shareholders: www.roche.com/info070625

Roche Group Media Office

Phone: +41 61 688 8888 / e-mail: basel.mediaoffice@roche.com

- Daniel Piller (Head of Roche Group Media Office)

- Baschi Dürr

Brunswick Group (for US media)

Phone: +1 212 333 3810

- Steve Lipin

- Nina Devlin

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

THIS DOCUMENT CONTAINS CERTAIN FORWARD-LOOKING STATEMENTS. THESE

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FORWARD-LOOKING STATEMENTS MAY BE IDENTIFIED BY WORDS SUCH AS ‘BELIEVES’, ‘EXPECTS’, ‘ANTICIPATES’, ‘PROJECTS’, ‘INTENDS’, ‘SHOULD’, ‘SEEKS’, ‘ESTIMATES’, ‘FUTURE’ OR SIMILAR EXPRESSIONS OR BY DISCUSSION OF, AMONG OTHER THINGS, STRATEGY, GOALS, PLANS OR INTENTIONS. VARIOUS FACTORS MAY CAUSE ACTUAL RESULTS TO DIFFER MATERIALLY IN THE FUTURE FROM THOSE REFLECTED IN FORWARD-LOOKING STATEMENTS CONTAINED IN THIS DOCUMENT, AMONG OTHERS: (1) PRICING AND PRODUCT INITIATIVES OF COMPETITORS; (2) LEGISLATIVE AND REGULATORY DEVELOPMENTS AND ECONOMIC CONDITIONS; (3) DELAY OR INABILITY IN OBTAINING REGULATORY APPROVALS OR BRINGING PRODUCTS TO MARKET; (4) FLUCTUATIONS IN CURRENCY EXCHANGE RATES AND GENERAL FINANCIAL MARKET CONDITIONS; (5) UNCERTAINTIES IN THE DISCOVERY, DEVELOPMENT OR MARKETING OF NEW PRODUCTS OR NEW USES OF EXISTING PRODUCTS, INCLUDING WITHOUT LIMITATION NEGATIVE RESULTS OF CLINICAL TRIALS OR RESEARCH PROJECTS, UNEXPECTED SIDE-EFFECTS OF PIPELINE OR MARKETED PRODUCTS; (6) INCREASED GOVERNMENT PRICING PRESSURES; (7) INTERRUPTIONS IN PRODUCTION; (8) LOSS OF OR INABILITY TO OBTAIN ADEQUATE PROTECTION FOR INTELLECTUAL PROPERTY RIGHTS; (9) LITIGATION; (10) LOSS OF KEY EXECUTIVES OR OTHER EMPLOYEES; AND (11) ADVERSE PUBLICITY AND NEWS COVERAGE. THE STATEMENT REGARDING EARNINGS PER SHARE GROWTH IS NOT A PROFIT FORECAST AND SHOULD NOT BE INTERPRETED TO MEAN THAT ROCHE’S EARNINGS OR EARNINGS PER SHARE FOR ANY CURRENT OR FUTURE PERIOD WILL NECESSARILY MATCH OR EXCEED THE HISTORICAL PUBLISHED EARNINGS OR EARNINGS PER SHARE OF ROCHE.

ADDITIONAL INFORMATION AND WHERE TO FIND IT

THIS PRESS RELEASE IS FOR INFORMATIONAL PURPOSES ONLY AND DOES NOT CONSTITUTE AN OFFER TO PURCHASE OR A SOLICITATION OF AN OFFER TO SELL VENTANA’S COMMON STOCK. THE TENDER OFFER IS BEING MADE PURSUANT TO A TENDER OFFER STATEMENT ON SCHEDULE TO (INCLUDING THE OFFER TO PURCHASE, LETTER OF TRANSMITTAL AND OTHER RELATED TENDER OFFER MATERIALS) FILED BY ROCHE WITH THE SECURITIES AND EXCHANGE COMMISSION (SEC) ON JUNE 27, 2007. THESE MATERIALS, AS THEY MAY BE AMENDED FROM TIME TO TIME, CONTAIN IMPORTANT INFORMATION, INCLUDING THE TERMS AND

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CONDITIONS OF THE OFFER, THAT SHOULD BE READ CAREFULLY BEFORE ANY DECISION IS MADE WITH RESPECT TO THE TENDER OFFER.  INVESTORS AND STOCKHOLDERS CAN OBTAIN A FREE COPY OF THESE MATERIALS AND OTHER DOCUMENTS FILED BY ROCHE WITH THE SEC AT THE WEBSITE MAINTAINED BY THE SEC AT WWW.SEC.GOV.  THE TENDER OFFER MATERIALS MAY ALSO BE OBTAINED FOR FREE BY CONTACTING THE INFORMATION AGENT FOR THE TENDER OFFER, MACKENZIE PARTNERS AT (212) 929-5500 OR (800) 322-2885 (TOLL-FREE).

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