Dr. Kathy Plesser, a Manhattan radiologist on the medical advisory board of Susan G. Komen for the Cure's New York chapter, said she plans to resign from her position unless Komen reverses its decision to pull grant money from Planned Parenthood.

"I’m a physician and my interest is women’s health, and I am disturbed by Komen’s decision because I am a very strong advocate for serving under-served women," Plesser told The Huffington Post. "Eliminating this funding will mean there’s no place for these women to go. Where are these women to go to have a mammography? Do they not deserve to have mammography?"

With her decision, Plesser joins Komen's top public health official, Mollie Williams, and the executive director of Komen's Los Angeles County chapter, Deb Anthony, both of whom also resigned in protest.

Susan G. Komen, the nation's largest breast cancer charity, announced on Tuesday that it had adopted a new rule against partnering with organizations that are under investigation, and that it would therefore sever ties with Planned Parenthood, which is currently under investigation in Congress. The groups that prompted that investigation are anti-abortion advocacy organizations that have long criticized Planned Parenthood, primarily a women's health and family planning organization, over the fact that some of its clinics offer abortions.

Komen has faced an increasing amount of pressure from the public, women's health groups, lawmakers and even some of its own regional affiliates to reverse the decision and continue its five-year partnership with Planned Parenthood. The $600,000 that Komen donated annually to the organization provided underserved women with free and low-cost breast exams.

Planned Parenthood announced Wednesday that it had received $400,000 in donations in the 24 hours following Komen's announcement. In addition, New York Mayor Mike Bloomberg said on Thursday that he would give $250,000 to Planned Parenthood to help make up for the loss.

“Politics have no place in health care,” he said in a statement. “Breast cancer screening saves lives and hundreds of thousands of women rely on Planned Parenthood for access to care. We should be helping women access that care, not placing barriers in their way."

A spokesperson for Rep. Mike Honda (D-Calif.) said that he personally called Komen founder Nancy Brinker to complain when he heard the news on Tuesday, and he and 22 other members of the House of Representatives have signed onto a letter asking her to reverse her decision.

"This is an alarming development resulting from political pressure from anti-women’s health organizations," the letter says. "We ask – in the strongest possible terms – that Susan G. Komen reconsider its decision, as the health of millions of brave women everywhere demands the same kind of bravery exhibited the Komen Foundation."

A similar letter was signed by two dozen senators.

Komen maintains that pressure from anti-abortion groups and the recent hiring of vice president Karen Handel, who ran for governor of Georgia on an anti-Planned Parenthood platform as a Republican in 2010, had nothing to do with the decision. Founder Nancy Brinker went on the defensive Thursday during an appearance on MSNBC, saying that the decision was a result of a number of congressional and state investigations into Planned Parenthood, and that most people actually applauded the decision to defund the family planning provider.

"All I can tell you is that the responses we're getting are very, very favorable," she told host Andrea Mitchell. "People who have bothered to read the material, who have bothered to understand the issues-- again, we work for a mission every day of our lives."

Honda, whose chief of staff is a breast cancer survivor, said he is concerned that Komen's decision will set a precedent, in which any politician can simply open an investigation into a group they disagree with now in order to jeopardize that group's funding.

"We know that breast cancer does not discriminate, nor should our support to vanquish the disease," he said.