Excel Conditional formatting for String

Hello,

I am trying to set excel conditional formatting cell fill, based on cell value which is a string. Can someone help me with the right code?

xlCellValue = 1;

xlEqual = 3;

Excel.Range(['G2:G' num2str(lastrow)]).Select;

Excel.Selection.FormatConditions.Add(xlCellValue, xlEqual, '=ABC');

Excel.Selection.FormatConditions.Item(3).Interior.ColorIndex = 46;

Thanks