As Pope Francis nears his first 100 days in office, there is little question he has brought about a change in style at the Vatican with his daily gestures of humility. But there are also signs he may bring about a change in substance.

In recent days, a leak of private comments Francis made to a group of Latin American Catholics has garnered big headlines in the Catholic world and is giving us the best insight so far into whether - and how - the pope intends to carry out needed reforms in the church.

The leak, published on the website of the left-of-center Chilean Catholic magazine Reflexion y Liberacion, quotes the pope as having told a delegation of the Latin American and Caribbean Confederation of Religious, known by its acronym CLAR, that he is confronting a network of "corruption" and a "gay lobby" within the Vatican that are allegedly resisting reforms.

His remarks at a June 6 private audience were apparently referring to the Vatican's financial scandals and coverups of sexual abuses by pedophile priests.

Perhaps more important, Francis told his visitors he is bent on reforming the Church, although the changes will be carried out by an eight-member commission of cardinals he has appointed.

"The reform in the Roman Church is something that all cardinals asked for in meetings prior to the conclave. I asked for it too," the Pope is quoted as telling his CLAR visitors. "The reform can't be done by me ... I am very disorganized. I've never been good at that. But the commission's cardinals will carry it out."

A CLAR statement later said it "profoundly laments" the unauthorized publication of the pope's remarks, which it said were not taped nor transcribed verbatim.

The Vatican said Tuesday it would not comment because the meeting was a private audience. The remarks are believed to be the pope's first admission that there are corrupt forces within the church.

In a telephone interview from Chile, reflexionyliberacion.cl editor Jaime Escobar told me that the pope's remarks are a clear sign that the pope intends to change the church for the better.

"While much of the world media has focused on the pope's references to 'corruption' and a 'gay lobby,' the most important part of what he said is that he has a mandate to reform the church," Escobar said. "The reform is coming."

Others are skeptical that the commission will adopt meaningful reforms. They argue its leader, Honduran Cardinal Oscar Rodriguez Madariaga, has been accused of covering up or unfairly dismissed child sex abuse claims. Rodriguez Madariaga has also been quoted suggesting Jews influenced the media to magnify cases of sexual abuse by priests - he later apologized, but Harvard law professor Alan Dershowitz called him an "anti-Semite" in a Feb. 14 letter to the Miami Herald.

My opinion: Francis' decision not to live in luxurious palace apartment of his predecessors but in the more modest Vatican guesthouse - where he is not exclusively surrounded by the church's hierarchy - and his remarks that he was elected with a mandate for reform are hopeful signs.

Granted, his remarks about the "gay lobby" in the Vatican are troublesome (although we don't know the exact context in which they were apparently said). And it would have been better if instead of deferring reforms to a commission, the pope had put aside his trademark modesty and taken the leadership himself.

But as long as it is clear to him that he has a mandate to reform the church, there's good reason to be optimistic.

Andres Oppenheimer writes for The Miami Herald. Readers can email him at aoppenheimer@miamiherald.com.